Power storage device and semiconductor device provided with the power storage device

ABSTRACT

An object is to provide a power storage device provided with a battery that is a power storage means, for safe and accurate supply of electric power in a short period of time for drive power supply voltage without checking remaining capacity of the battery or changing batteries with deterioration over time of the battery for drive power supply voltage. The power storage device is provided with a battery that is a power storage means as a power supply for supplying electric power and a counter circuit for counting charging time of the power storage means. An electromagnetic wave with electric field intensity, magnetic field intensity, and power flux density per unit time which are transmitted from a power feeder are controlled, and the power storage means is efficiently charged using the electromagnetic wave in a short period of time.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a power storage device. In particular,the present invention relates to a power storage device which is chargedwith electric power through an electromagnetic wave. Furthermore, thepresent invention relates to a charging system using a power storagedevice provided with an antenna and a power feeder which supplieselectric power to the power storage device through an electromagneticwave.

A “power storage device” mentioned in this specification refers to ageneral device which stores electric power by an electromagnetic wavetransmitted from an external power supply device (power feeder). Inaddition, a battery which stores power by wireless reception of anelectromagnetic wave is referred to as a wireless battery (RF battery:Radio Frequency Battery).

2. Description of the Related Art

Various electronic appliances are coming into wide use, and a widevariety of products are on the market. In particular, in recent years,the spread of portable electronic appliances has been marked. Forexample, mobile phones, digital video cameras, and the like have becomevery convenient because of high-definition display portions, increaseddurability of batteries, and further reduction in power consumption ofthe batteries. A portable electronic appliance has a structure in whicha battery that is a power storage means is built in. Thus, a powersupply for driving the portable electronic appliance is secured by thebattery. As matters now stand, as the battery, a battery such as alithium ion battery is used, and the battery is directly charged from anAC adaptor which is plugged into a household AC power supply that is apower supply means.

Moreover, in recent years, development of a power storage device whichstores electric energy wirelessly so that a portable appliance can becharged also in a place without a commercial power supply has beenadvanced (e.g., see Patent Document 1: Japanese Published PatentApplication No. 2003-299255).

SUMMARY OF THE INVENTION

However, in an example of a power storage device described in PatentDocument 1, when an electromagnetic wave with high electric fieldintensity is supplied to the power storage device for supplying highelectric power in a short period of time, effects on the human body areconcerned. In addition, as for supply of an electromagnetic wave withhigh electric field intensity to a power storage device for supplyinghigh electric power in a short period of time, there is a regalregulation on transmission of an electromagnetic wave with a certainamount or more of electric field intensity, magnetic field intensity, orpower flux density per unit time.

Moreover, when a power storage device is charged, especially when aplurality of power storage devices is charged, they might not besufficiently charged with electromagnetic wave attenuation. For example,there has been a problem in that if voltage applied to a batteryincluded in the power storage device is not higher than a certain value,charging is not performed in some cases, and accordingly, it is hard tocharge the plurality of power storage devices.

There has been a problem in that when charging of a power storage deviceis completed or interrupted for some cause, measures such as preventionmeasures against overcharging and stop of supply of unnecessary electricpower through an electromagnetic wave are taken on a power feeder, undera condition that electric power is intermittently supplied from thepower feeder through the electromagnetic wave.

It is an object of the present invention to provide a power storagedevice provided with a battery that is a power storage means, for safeand accurate supply of electric power in a short period of time fordrive power supply voltage without checking remaining capacity of thebattery or changing batteries with deterioration over time of thebattery for drive power supply voltage.

In order to solve the above-described problems, it is a feature of thepresent invention that a power storage device is provided with a batterythat is a power storage means as a power supply for supplying electricpower and a counter circuit for counting storage time of the powerstorage means. According to another feature of the present invention, anelectromagnetic wave with electric field intensity, magnetic fieldintensity, and power flux density per unit time, which is transmittedfrom a power feeder, is controlled and the power storage means isefficiently charged using the electromagnetic wave in a short period oftime. Hereinafter, a specific structure of the present invention isdescribed.

According to one feature of the present invention, a power storagedevice includes an antenna; a battery; a power supply portion includinga rectifier circuit connected to the antenna, a charging control circuitthat is connected to the rectifier circuit and controls charging of thebattery, and a power supply circuit that is connected to the battery andcontrols electric power supplied to a load; and a charging determinationportion including a demodulation circuit that demodulates a signalinputted to the antenna, a determination circuit that determines whetherthe battery is in a charging state or a non-charging state in accordancewith the signal and outputs a signal that switches the charging stateand the non-charging state, a counter circuit that counts charging timeof the battery and outputs the counted time to the determinationcircuit, and a modulation circuit that modulates a signal to beoutputted to an external portion in accordance with the charging stateor the non-charging state determined by the determination circuit.

According to another feature of the present invention, a power storagedevice includes an antenna; a battery; a charging management circuitconnected to the battery; a power supply portion including a rectifiercircuit connected to the antenna, a charging control circuit that isconnected to the rectifier circuit and controls charging of the battery,and a power supply circuit that is connected to the battery and controlselectric power supplied to a load; and a charging determination portionincluding a demodulation circuit that demodulates a signal inputted tothe antenna, a determination circuit that determines whether the batteryis in a charging state or a non-charging state in accordance with thesignal and outputs a signal that switches the charging state and thenon-charging state, a counter circuit that counts charging time of thebattery and outputs the counted time to the determination circuit, and amodulation circuit that modulates a signal to be outputted to anexternal portion in accordance with the charging state or thenon-charging state determined by the determination circuit, or a signalfrom the charging management circuit.

The battery of the present invention may be a lithium battery, a nickelmetal hydride battery, a nickel cadmium battery, an organic radicalbattery, or a double-layer electrolytic capacitor.

The battery of the present invention may be formed of a negativeelectrode active material layer, a solid electrolyte layer over thenegative electrode active material layer, a positive electrode activematerial layer over the solid electrolyte layer, and acurrent-collecting thin film over the positive electrode active materiallayer.

The charging control circuit of the present invention may have aregulator and a diode.

The charging control circuit of the present invention may have astructure including a regulator and a switch, in which the switch is ina conductive state when the determination circuit determines that theswitch is in a charging state and is in a nonconductive state when thedetermination circuit determines that the switch is in a non-chargingstate.

The power supply circuit of the present invention may have a structureincluding a regulator and a switch, in which the switch is in anonconductive state when the determination circuit determines that theswitch is in a charging state and is in a conductive state when thedetermination circuit determines that the switch is in a non-chargingstate.

In the present invention, the power supply circuit may include a Schmitttrigger.

The present invention includes a semiconductor device in which a load isa signal processing circuit which includes an amplifier, a modulationcircuit, a demodulation circuit, a logic circuit, a memory controlcircuit, and a memory circuit.

The semiconductor device of the present invention is an IC label, an ICtag, or an IC card.

It is to be noted that description “being connected” in the presentinvention includes electrical connection and direct connection.Therefore, in structures disclosed in the present invention, anotherelement capable of electrical connection (e.g., a switch, a transistor,a capacitor, an inductor, a resistor, a diode, or the like) may beinterposed between elements having a predetermined connection relation.Alternatively, the elements may be directly connected without anotherelement interposed therebetween. It is to be noted that the case wherethe connection is directly performed without any element capable ofelectrical connection interposed therebetween, which is the caseincluding only the state of direct connection except for the case wherethe connection is electrically performed, is described as “beingdirectly connected”. It is to be noted that description “beingelectrically connected” includes either the state where the connectionis electrically performed or the state where the connection is directlyperformed.

Since the power storage device of the present invention employs astructure having a power storage means, electric power can be suppliedto a load without checking remaining capacity of the battery or changingbatteries with deterioration over time of the battery for drive powersupply voltage.

In addition, the power storage device of the present invention isprovided with the circuit that responds to the power feeder thatsupplies an electromagnetic wave for charging the battery whether thepower storage device is in a charging state or a non-charging state;therefore, when charging of the power storage device is completed or thecharging thereof is interrupted for some cause, unnecessary supply ofelectric power by an electromagnetic wave can be stopped. Moreover, thepower storage device is provided with the circuit that responds to thepower feeder whether the power storage device is in a charging state ora non-charging state, so that the circuit can inform that a plurality ofpower storage devices is charged by the power feeder, and a powerstorage device to be charged can be selected to perform charging. Thatis, even when charging of a plurality of power storage devices is notsufficiently performed due to electromagnetic wave attenuation, theplurality of power storage devices can be separately charged.

Moreover, since the power storage device of the present invention isprovided with the counter circuit inside, the power storage device canreceive an electromagnetic wave with a certain amount or more ofelectric field intensity, magnetic field intensity, or power fluxdensity even if the average of electric power is the same.

BRIEF DESCRIPTION OF DRAWINGS

In the accompanying drawings:

FIG. 1 is a diagram explaining a structure of Embodiment Mode 1;

FIGS. 2A and 2B are diagrams each explaining a structure of EmbodimentMode 1;

FIGS. 3A to 3C are diagrams each explaining a structure of EmbodimentMode 1;

FIGS. 4A and 4B are diagrams each explaining a structure of EmbodimentMode 1;

FIGS. 5A and 5B are diagrams each explaining a structure of EmbodimentMode 1;

FIG. 6 is a flow chart explaining a structure of Embodiment Mode 1;

FIG. 7 is a diagram explaining a structure of Embodiment Mode 1;

FIG. 8 is a diagram explaining a structure of Embodiment Mode 1;

FIG. 9 is a diagram explaining a structure of Embodiment Mode 1;

FIG. 10 is a flow chart explaining a structure of Embodiment Mode 1;

FIG. 11 is a diagram explaining a structure of Embodiment Mode 2;

FIG. 12 is a diagram explaining a structure of Embodiment Mode 2;

FIG. 13 is a diagram explaining a structure of Embodiment Mode 2;

FIG. 14 is a diagram explaining a structure of Embodiment Mode 3;

FIG. 15 is a diagram explaining a structure of Embodiment 1;

FIGS. 16A to 16E are views each explaining a structure of Embodiment 5;

FIGS. 17A and 17B are diagrams each explaining a structure of Embodiment4;

FIGS. 18A to 18D are diagrams each explaining a structure of Embodiment2;

FIGS. 19A to 19C are diagrams each explaining a structure of Embodiment2;

FIGS. 20A and 20B are diagrams each explaining a structure of Embodiment2;

FIGS. 21A and 21B are diagrams each explaining a structure of Embodiment2;

FIGS. 22A and 22B are diagrams each explaining a structure of Embodiment2;

FIGS. 23A to 23C are diagrams each explaining a structure of Embodiment3;

FIGS. 24A to 24C are diagrams each explaining a structure of Embodiment3;

FIGS. 25A and 25B are diagrams each explaining a structure of Embodiment3;

FIGS. 26A to 26C are diagrams each explaining a structure of Embodiment4;

FIGS. 27A to 27C are diagrams each explaining a structure of Embodiment4;

FIGS. 28A to 28C are diagrams each explaining a structure of Embodiment4; and

FIGS. 29A and 29B are diagrams each explaining a structure of EmbodimentMode 1.

DETAILED DESCRIPTION OF THE INVENTION

Embodiment modes of the present invention will be hereinafter explainedwith reference to the accompanying drawings. However, the presentinvention can be carried out in many different modes, and it is easilyunderstood by those skilled in the art that modes and details of thepresent invention can be modified in various ways without departing fromthe purpose and the scope of the present invention. Therefore, thepresent invention should not be interpreted as being limited to thedescription of Embodiment Modes. It is to be noted that, in the drawingshereinafter shown, the same portions or portions having similarfunctions are denoted by the same reference numerals, and repeatedexplanation thereof will be omitted.

Embodiment Mode 1

One structural example of a power storage device of the presentinvention will be explained with reference to block diagrams shown inFIG. 1 and FIGS. 2A and 2B. It is to be noted that the case where thepower storage device is charged by a power feeder that is a power supplymeans will be explained in this embodiment mode.

A power storage device 100 shown in FIG. 1 includes an antenna 101, apower supply portion 102, a charging determination portion 103, and abattery 104. Electric power is supplied to the power storage device 100by a power feeder 151, and the electric power stored in the battery 104in the power storage device 100 is supplied to a load 152. The powersupply portion 102 includes a rectifier circuit 105 that rectifies anelectromagnetic wave inputted to the antenna 101, a charging controlcircuit 106 that controls charging of the battery 104 with electricpower from the rectifier circuit 105, and a power supply circuit 107 forcontrolling supply of the electric power charged by the battery 104 tothe load 152. The charging determination portion 103 includes ademodulation circuit 108 for demodulating a signal inputted to theantenna 101, a determination circuit 109 that determines whether thebattery 104 is in a charging state or in a non-charging state inaccordance with the signal inputted from the antenna 101 and outputs asignal for switching the charging state and the non-charging state, acounter circuit 110 for counting charging time of the battery 104 andoutputting the counted time to the determination circuit 109, and amodulation circuit 111 for modulating a signal to be outputted to anexternal portion in accordance with the charging state or thenon-charging state determined by the determination circuit 109.

A structure of the power supply portion 102 is explained in detail.

In the power storage device 100 shown in FIG. 1, the antenna 101receives an electromagnetic wave from the power feeder 151 and outputsthe electromagnetic wave to the rectifier circuit 105. It is to be notedthat as an electromagnetic wave transmission method applied between theantenna 101 in the power storage device 100 of the present invention andthe power feeder 151, an electromagnetic coupling method, anelectromagnetic induction method, a microwave method, and the like canbe employed. The transmission method may be appropriately selected by apractitioner in consideration of an intended use. An antenna withoptimal length and shape may be provided in accordance with thetransmission method.

In the case of employing, for example, an electromagnetic couplingmethod or an electromagnetic induction method (e.g., a 13.56 MHz band)as the transmission method, electromagnetic induction caused by a changein magnetic field density is used. Therefore, a conductive filmfunctioning as an antenna is formed in an annular shape (e.g., a loopantenna) or a spiral shape (e.g., a spiral antenna). A specific exampleof an antenna circuit is shown in FIG. 2A. In FIG. 2A, the antenna 101includes an antenna coil 201 and a resonance capacitor 202. It is to benoted that, in the antenna 101 shown in FIG. 2A, the antenna coil 201and the resonance capacitor 202 are connected in parallel. In thestructure shown in FIG. 2A, a variable capacitor is used as theresonance capacitor 202 and the capacitance value is controlled, so thatthe frequency of a received electromagnetic wave can be variable.

In the case of employing a microwave method (e.g., a UHF band (860 to960 MHz band), a 2.45 GHz band, or the like) as the transmission system,a length or a shape of the conductive film functioning as an antenna maybe appropriately set in consideration of a wavelength of anelectromagnetic wave used for signal transmission. The conductive filmfunctioning as an antenna can be formed in, for example, a linear shape(e.g., a dipole antenna), a flat shape (e.g., a patch antenna), and thelike. The shape of the conductive film functioning as an antenna is notlimited to a linear shape, and the conductive film functioning as anantenna may be formed in a curved-line shape, a meander shape, or acombination thereof, in consideration of the wavelength of theelectromagnetic wave.

It is to be noted that antennas with a plurality of shapes may becombined to be formed as one antenna and an antenna corresponding toreception of an electromagnetic wave with a plurality of frequency bandsmay be employed as the antenna 101 in the power storage device 100 ofthe present invention. A shape of an antenna is shown in FIGS. 29A and29B as an example. For example, a structure may be employed, as shown inFIG. 29A, in which an antenna 2902A and an antenna 2902B that is 180°omnidirectional (capable of receiving from any direction) are providedall around a chip 2901 provided with a power supply portion, a chargingdetermination portion, and the like. In addition, a structure may alsobe employed, as shown in FIG. 29B, in which a thin coiled antenna 2902C,an antenna 2902D for receiving an electromagnetic wave with highfrequency, and an antenna 2902E that is extended in a stick shape areprovided around the chip 2901 provided with the power supply portion,the charging determination portion, and the like. The antennas with aplurality of shapes are provided as shown in FIGS. 29A and 29B, so thata power storage device corresponding to reception of electromagneticwaves with a plurality of frequency bands can be obtained.

The frequency of an electromagnetic wave transmitted from the powerfeeder 151 to the antenna 101 is not particularly limited. For example,any of the following frequencies can be used: greater than or equal to300 GHz and less than 3 THz that is a submillimeter wave, greater thanor equal to 30 GHz and less than 300 GHz that is a millimeter wave,greater than or equal to 3 GHz and less than 30 GHz that is a microwave,greater than or equal to 300 MHz and less than 3 GHz that is anultrahigh frequency wave, greater than or equal to 30 MHz and less than300 MHz that is a very high frequency wave, greater than or equal to 3MHz and less than 30 MHz that is a high frequency wave, greater than orequal to 300 kHz and less than 3 MHz that is a medium frequency wave,greater than or equal to 30 kHz and less than 300 kHz that is a lowfrequency wave, and greater than or equal to 3 kHz and less than 30 kHzthat is a very low frequency wave.

In addition, in the present invention, a signal indicating to the powerfeeder 151 whether the power storage device 100 is in a charging stateor a non-charging state is transmitted and received between the powerfeeder 151 and the power storage device 100. An electromagnetic wavetransmitted from the power feeder 151 to the antenna 101 at this time isa signal of which a carrier wave is modulated. A modulation method ofthe carrier wave may be either one of analog modulation or digitalmodulation, or any of amplitude modulation, phase modulation, frequencymodulation, and spread spectrum. Amplitude modulation or frequencymodulation is desirably employed.

Moreover, the frequency of an electromagnetic wave for charging and thefrequency of an electromagnetic wave for communication for startingcharging, which are transmitted from the power feeder 151 to the powerstorage device 100, may be different from each other. In that case, asthe electromagnetic wave for charging, an electromagnetic wave withequal amplitude as shown in FIG. 3A can be employed, and as theelectromagnetic wave for communication, an electromagnetic wave withdifferent amplitude as shown in FIG. 3B or 3C can be employed. Inaddition, as the electromagnetic wave for communication, anelectromagnetic wave with a different frequency or a different phase canbe employed as well.

In the power storage device 100 in FIG. 1, an electromagnetic waveinputted from the power feeder 151 to the antenna 101 is converted intoan AC electric signal by the antenna 101 and rectified by the rectifiercircuit 105. It is to be noted that the rectifier circuit 105 isacceptable as long as it is a circuit that converts an AC signal inducedby an electromagnetic wave received by the antenna 101 into a DC signalby rectification and smoothing. For example, as shown in FIG. 2B, therectifier circuit 105 may include a diode 203 and a smoothing capacitor204.

In the power storage device 100 in FIG. 1, the electric signal rectifiedby the rectifier circuit 105 is inputted to the charging control circuit106. The charging control circuit 106 controls the voltage level of theelectric signal inputted from the rectifier circuit 105 and outputs theelectric signal of which the voltage level has been controlled to thebattery 104. A specific structure of the charging control circuit 106 isshown in FIG. 4A. The charging control circuit 106 shown in FIG. 4Aincludes a regulator 401 that is a circuit for controlling voltage and aswitch 402. It is to be noted that on and off of the switch 402 iscontrolled by a determination result by the determination circuit 109,in which whether the power storage device is in a charging state or anon-charging state. It is to be noted that the switch 402 is turned onwhen the power storage device 100 is in a charging state and turned offwhen the power storage device 100 is in a non-charging state, so thatelectric power stored in the battery 104 can be prevented from leaking.Thus, as shown in FIG. 4B, a structure can be employed in which theswitch 402 is replaced with a diode 403 with a rectifying property. Whenthe diode 403 is used instead of the switch 402, input of a signal forswitching on and off of the switch can be omitted.

In the power storage device 100 shown in FIG. 1, the electric signal ofwhich the voltage level has been controlled by the charging controlcircuit 106 is inputted to the battery 104, so that the battery 104 ischarged. In the present invention, a “battery” refers to a power storagemeans whose continuous operating time can be restored by charging. It isto be noted that, although a secondary battery, a capacitor, and thelike are given as the power storage means, they are referred to as abattery as a collective term in this specification. A battery formed ina sheet-like form is preferably used although depending on an intendeduse. For example, reduction in size is possible with the use of alithium battery, preferably a lithium polymer battery that uses a gelelectrolyte, a lithium ion battery, or the like. Needless to say, anybattery may be used as long as it is chargeable, and a battery that ischargeable and dischargeable, such as a nickel metal hydride battery, anickel cadmium battery, an organic radical battery, a lead storagebattery, an air secondary battery, a nickel zinc battery, or a silverzinc battery may be used. Alternatively, a high-capacity capacitor orthe like may be used.

It is to be noted that as a high-capacity capacitor that can be used asa battery of the present invention, it is preferable to use a capacitorhaving electrodes whose opposed areas are large. It is preferable to usea double-layer electrolytic capacitor formed using an electrode materialhaving a large specific surface area, such as activated carbon,fullerene, or a carbon nanotube. A capacitor has a simple structure andis easily formed to be thin and formed as a stacked layer. Adouble-layer electrolytic capacitor is preferable because it has afunction of storing power, does not deteriorate much even after thenumber of times of charging and discharging is increased, and has anexcellent rapid charging property.

In addition, in this embodiment mode, electric power stored in thebattery is not limited to an electromagnetic wave outputted from thepower feeder 151, and a structure may be employed in which a powergeneration element is additionally provided in part of the power storagedevice. Employing the structure in which a power generation element isadditionally provided is advantageous because the amount of electricpower supplied to be stored in the battery 104 can be increased and thecharging rate can be increased.

It is to be noted that as the power generation element, for example, apower generation element using a solar battery, a power generationelement using a piezoelectric element, or a power generation elementusing a micro electro mechanical system (MEMS) may be used.

In the power storage device 100 in FIG. 1, the electric power stored inthe battery 104 is inputted to the power supply circuit 107. The powersupply circuit 107 controls the voltage level of an electric signaloutputted from the battery 104 and controls supply of the electric powerstored in the battery 104 to the load 152. A specific structure of thepower supply circuit 107 is shown in FIG. 5A. The power supply circuit107 shown in FIG. 5A includes a switch 501 and a regulator 502 that is acircuit for controlling voltage. It is to be noted that on and off ofthe switch 501 are controlled by a determination result by thedetermination circuit 109, in which whether the power storage device 100is in a charging state or a non-charging state.

In the power supply circuit 107, a structure may be employed in which aSchmitt trigger is combined in the structure of the switch 501 shown inFIG. 5A. A specific structure provided with a Schmitt trigger is shownin FIG. 5B. In a Schmitt trigger 503 shown in FIG. 5B, a switchingelement can have hysteresis. Thus, in the power storage device 100, theswitch can be kept on even if the capacity of the electric power of thebattery is decreased and output voltage is decreased; accordingly,supply of electric power to the load 152 can be kept for a long periodof time.

Next, a structure of the power feeder 151 is explained in detail.

The power feeder 151 in FIG. 1 outputs to the power storage device 100an electromagnetic wave for charging the battery 104 in the powerstorage device 100 and a charging starting signal for starting chargingof the power storage device 100. In addition, the power feeder 151receives a signal indicating whether the power storage device 100 is ina charging state or a non-charging state from the power storage device100. A specific structure of the power feeder 151 is shown in FIG. 7.The power feeder 151 in FIG. 7 includes a transmitting antenna 601, areceiving antenna 602, a transmitting portion 603, a receiving portion604, and a control portion 605. The transmitting antenna 601 includes anantenna coil 606 and a resonance capacitor 608. In addition, thereceiving antenna 602 includes an antenna coil 607 and a resonancecapacitor 609. The control portion 605 controls the receiving portion604 and the transmitting portion 603 in accordance with each of acharging starting signal output order, a power supply processing order,a receiving signal processing order, and a standby order. Thetransmitting portion 603 modulates a charging starting signal to betransmitted to the power storage device 100, and outputs the chargingstarting signal through the antenna 601 as an electromagnetic wave. Inaddition, the receiving portion 604 demodulates the signal received bythe antenna 602 and outputs the demodulated signal to the controlportion 605 as a processing result of the received signal.

It is to be noted that in the power feeder 151 in FIG. 7, either one ofthe transmitting antenna 601 and the receiving antenna 602 is used,whereby one antenna functions as both antennas and one of them may beeliminated. Either one of the transmitting antenna 601 or the receivingantenna 602 functions as both antennas, so that the size of the powersupply portion 151 can be reduced.

Next, a structure of the charging determination portion 103 is explainedin detail.

In the power storage device 100 in FIG. 1, the demodulation circuit 108generates a demodulated signal with a frequency lower than that of an ACsignal received by the antenna 101, based on an AC signal received bythe antenna 101, and outputs the demodulated signal to the determinationcircuit 109. It is to be noted that the demodulated signal is outputtedto the determination circuit 109 as a digital signal based on a signalof which a carrier wave is modulated transmitted from the power feeder151. In addition, the modulation circuit 111 modulates a high-frequencycarrier wave outputted from an antenna circuit based on a signaloutputted from the determination circuit 109, and outputs thehigh-frequency carrier wave to the power feeder 151 through the antenna101.

It is to be noted that the demodulation circuit 108 has a similarfunction to that of the rectifier circuit 105 in the power supplyportion 102. Therefore, a structure may also be employed in which therectifier circuit 105 generates a demodulated signal with a frequencylower than that of an AC signal received by the antenna 101, based onthe AC signal received by the antenna 101 and outputs the signal to thedetermination circuit 109. In this case, the power storage device 100can be formed without the demodulation circuit 108; therefore, reductionin size of the power storage device can be achieved.

In the power storage device 100 in FIG. 1, the determination circuit 109determines whether the power storage device 100 is in a charging stateor a non-charging state to output a signal. As described above, thedetermination circuit 109 in FIG. 1 monitors (checks) the voltage valueof the battery 104, controls on and off of the switch 402 in thecharging control circuit 106 and the switch 501 in the power supplycircuit 107, processes data of a signal from the modulation circuit 108,and outputs a signal for being outputted to the power feeder 151 to themodulation circuit 111.

The determination circuit 109 determines whether charging of the battery104 is completed by monitoring the voltage value of the battery 104. Adata signal received by the antenna 101 when the charging is started orthe charging is completed is inputted to the determination circuit 109through the demodulation circuit 108, so that the determination circuit109 determines whether the power storage device is in a charging stateor a non-charging state based on the a signal waveform of the datasignal. In addition, a signal for being outputted to the power feeder151 is outputted to the modulation circuit 111 based on a signal with aconstant period from the counter circuit 110. A typical waveform of adata signal when charging is started and an electromagnetic wave duringcharging is shown in FIG. 8. As amplitude of a data signal and amplitudeof an electromagnetic wave in a charging state, the amplitude of theelectromagnetic wave is made large. The amplitude of the electromagneticwave is made large, so that voltage of a signal received by the powerstorage device 100 in a charging state can be made high, andaccordingly, charging can be performed more surely.

In the power storage device 100 in FIG. 1, the counter circuit 110 is acircuit for counting time from when the charging state of the powerstorage device 100 is started. The counter circuit 110 generates a resetsignal based on a signal for stating charging from the power feeder 151(hereinafter, referred to as a charging starting signal), which isinputted to the demodulation circuit 108, so that a counter operates.Logic circuits such as flip flop circuits are combined for forming thecounter circuit 110, and a clock signal is inputted from a clockgeneration circuit such as a ring oscillator or a crystal oscillator, sothat the time is counted. It is to be noted that the clock generationcircuit may be formed so as to be directly supplied with electric powerfrom the battery 104.

Moreover, as described above, the counter circuit 110 outputs a signalwith a constant period to the modulation circuit 111, which is for beingoutputted to the power feeder 151, to the determination circuit 109. Thesignal may be formed so as to be outputted when a counter value in thecounter circuit 110 is carried. In addition, the counter circuit 110counts a charging period of the power storage device 100 in a chargingstate and receives an electromagnetic wave with a certain amount or moreof electric field intensity, magnetic field intensity, or power fluxdensity even if the average of electric power from the power feeder 151is the same. Then, after a charging state for a certain period, outputof the signal with a constant period to the modulation circuit 111,which is for being outputted to the power feeder 151, to thedetermination circuit 109 is stopped. Then, charging of the powerstorage device 100 by an electromagnetic wave from the power feeder isstopped, so that the power storage device 100 can store anelectromagnetic wave with a certain amount or more of electric fieldintensity, magnetic field intensity, or power flux density even if theaverage of electric power is the same.

An operation of the determination circuit 109 is explained using a flowchart shown in FIG. 6.

In FIG. 6, as a simple example, the case where one power storage device100 is provided within a space an electrimagnetic wave supplied by thepower feeder 151 reaches is explained. In FIG. 6, first, the powerfeeder 151 transmits a charging starting signal to the power storagedevice 100, and the power storage device 100 receives the chargingstarting signal (S701).

Next, the power storage device 100 which has received the chargingstarting signal switches on and off of each switch in the power storagedevice 100 in order to be switched from a non-charging state to acharging state in the determination circuit 109. Specifically, the powerstorage device 100 turns on the switch 402 in the charging controlcircuit 106 and turns off the switch 501 in the power supply circuit 107(S702).

Next, the power feeder 151 supplies an electromagnetic wave for chargingthe battery 104 to the antenna 101 of the power storage device 100(S703).

In addition, in the power storage device 100, the counter circuit 110counts a period in which the electromagnetic wave for charging thebattery 104, which is outputted from the power feeder 151, is inputted.In the period in which the battery 104 of the power storage device 100is charged, the power storage device 100 regularly transmits a signalfor informing the power feeder 151 side whether the power feeder 151 andthe power storage device 100 are in a wireless charging state (S704).

As described above, the determination circuit 109 determines whether thepower storage device 100 is in a charging state or a non-charging state.The determination circuit 109 outputs a periodic signal to themodulation circuit 111 in accordance with a counter value from thecounter circuit 110. Then, the power storage device 100 in the chargingstate regularly transmits the signal to the power feeder 151. It is tobe noted that in the counter circuit 110, in the case where thedetermination circuit 109 monitors voltage of the battery 104 in acounting period and determines that charging of the battery 104 iscompleted (hereinafter, referred to as full charging), output of thesignal to the power feeder 151, which is described above, is stopped.Then, in the case where the power feeder 151 receives the signal fromthe power storage device 100 (NO in S705), the power feeder 151continuously supplies an electromagnetic wave for charging the battery104 to the power storage device 100.

Moreover, in the case where the power feeder 151 does not receive thesignal from the power storage device 100 (YES in S705), the power feeder151 stops supplying an electromagnetic wave for charging the battery104. That is, the power storage device 100 does not receive the signalfor charging the battery 104; thus, the power storage device 100 movesto a non-charging state (S706). It is to be noted that also in the casewhere the power storage device 100 outputs a signal indicating acharging state, when the signal indicating the charging state is notsupplied to the power feeder 151 side due to communication conditions orthe like, the power storage device 100 moves to a non-charging stateeven if the battery 104 is not fully charged.

Next, the power storage device 100 which has moved to the non-chargingstate is changed from a charging state to a non-charging state in thedetermination circuit 109, and the power storage device 100 switches onand off of each switch. Specifically, the power storage device 100 turnsoff the switch 402 in the charging control circuit 106 and turns on theswitch 501 in the power supply circuit 107 (S707).

Then, in the case where the battery 104 in the power storage device 100is not fully charged, the power feeder 151 outputs a charging startingsignal again, so that the power storage device 100 is charged (NO inS708). In addition, in the case where the battery 104 in the powerstorage device 100 is fully charged, charging of the power storagedevice 100 is completed (YES in S708).

Subsequently, a signal for controlling on and off of the switch 402 inthe charging control circuit 106 and the switch 501 in the power supplycircuit 107, which is outputted from the determination circuit 109, andan output signal, which is for being outputted to the power feeder 151,to the modulation circuit 111 are explained using a timing chart. It isto be noted that explanation is given under the condition that eachswitch is an N-channel transistor, and the switch is turned on when ahigh potential signal is outputted and it is turned off when a lowpotential signal is outputted. In addition, explanation is given underthe condition that, output from the determination circuit 109 to themodulation circuit 111 starts when a high potential signal is outputtedto the switch 402.

In FIG. 9, in the non-charging state, as described above, the switch 402is turned off and the switch 501 is turned on, and an output signal,which is for output indicating a charging state to the power feeder 151,to the modulation circuit 111 is stopped. Therefore, in the non-chargingstate, output from the determination circuit 109 to the switch 402becomes a low potential signal, output from the determination circuit109 to the switch 501 becomes a high potential signal, and output fromthe determination circuit 109 to the modulation circuit 111 becomes alow potential signal. In the charging state, as described above, theswitch 402 is turned on, the switch 501 is turned off, and the outputsignal, which is for output indicating a charging state to the powerfeeder 151, to the modulation circuit 111 is outputted at a constantperiod. Therefore, in the charging state, output from the determinationcircuit 109 to the switch 402 becomes a high potential signal, outputfrom the determination circuit 109 to the switch 501 becomes a lowpotential signal, and a high potential signal (a high potential signal901A and a high potential signal 901B in FIG. 9) is outputted from thedetermination circuit 109 to the modulation circuit 111 at a constantperiod, based on a signal from the counter circuit.

In the timing chart in FIG. 9, when charging of the power storage device100 is completed or the charging thereof is interrupted due to somecause, the determination circuit 109 stops output of a high potentialsignal to the modulation circuit 111 at a constant period (a highfrequency signal 902 shown by dotted lines). Therefore, the power feeder151 stops output of an electromagnetic wave for charging the battery 104in the power storage device 100. Since the power storage device 100 doesnot receive the electromagnetic wave for charging the battery 104 atthis time, the determination circuit 109 determines that the powerstorage device 100 is in a non-charging state and each switch iscontrolled as shown by dotted lines 903 and dotted lines 904 in FIG. 9.In the structure of the present invention, as described above, thecharging state and the non-charging state are determined and switched bythe inputted signal, so that unnecessary supply of electric power by theelectromagnetic wave can be stopped and automatic return to thenon-charging state can be performed.

In FIG. 10, the case where a plurality of power storage devices 100 isprovided within a space an electromagnetic wave supplied by the powerfeeder 151 reaches is explained using a flow chart. In FIG. 10, first,the power feeder 151 transmits a charging starting signal to the powerstorage device 100, and the plurality of power storage devices 100receives a charging starting signal (S1001).

Next, each of the plurality of power storage devices 100 that hasreceived the charging starting signal switches on and off of each switchin order to be switched from a non-charging state to a charging state bythe determination circuit 109. Specifically, the power storage device100 turns on the switch 402 in the charging control circuit 106 andturns off the switch 501 in the power supply circuit 107 (S1002).

Next, the power feeder 151 supplies an electromagnetic wave for chargingthe battery 104 to the antenna 101 in each of the plurality of powerstorage devices 100 (S1003).

In addition, in each of the plurality of power storage devices 100, thecounter circuit 110 counts a period in which the electromagnetic wavefor charging the battery 104 outputted from the power feeder 151 isinputted. In the period in which the battery 104 of each of theplurality of power storage devices 100 is charged, each of the powerstorage devices 100 regularly transmits a signal for informing the powerfeeder 151 side whether the power feeder 151 and the power storagedevice 100 are in a wireless charging state (S1004).

In the case where the plurality of power storage devices 100 is providedwithin the space the electromagnetic wave supplied by the power feeder151 reaches, a plurality of signals for informing the power feeder 151side whether the power feeder 151 and the power storage device 100 inS1004 are in a wireless charging state are received on the power feeder151 side (S1005). In the case where the plurality of power storagedevices 100 is provided within the space the electromagnetic wavesupplied by the power feeder 151 reaches (YES in S1005), the powerfeeder 151 selects a power storage device for charging (S1006). That is,a charging stopping signal is transmitted to power feeders except forthe power feeder for charging. The power storage device to which thecharging stopping signal has been transmitted is not charged by thepower feeder 151 during a period in which the counter circuit 110counts.

It is to be noted that, in S1006, an identification number may be givento each of the plurality of power storage devices in order to identifythe plurality of power storage devices and the identification number maybe stored in memory or the like in advance, so that the power storagedevice to be charged or not to be charged is selected.

Next, the power storage device selected in S1006 is anew charged(S1007). The power storage device may be charged at this time inaccordance with the flow chart shown in FIG. 6. It is to be noted that,in S1005, S1007 starts after S1005, in the case where the plurality ofpower storage devices 100 is not provided within the space theelectromagnetic wave supplied by the power feeder 151 reaches (NO inS1005).

Then, after charging of the given power storage device is completed,another power storage device is charged. In the case where a powerstorage device in which charging is not performed is provided within thespace the electromagnetic wave supplied by the power feeder 151 reaches(NO in S1008), S1001 starts again. In addition, in the case where thepower storage device in which charging is not performed is not providedwithin the space the electromagnetic wave supplied by the power feeder151 reaches (YES in S1008), charging of the plurality of power storagedevices is determined to be completed.

As described above, the power storage device of the present inventionemploys the structure with the power storage means; therefore, electricpower can be supplied to the load without checking remaining capacity ofthe battery or changing batteries with deterioration over time of thebattery for drive power supply voltage. In addition, the power storagedevice of the present invention is provided with the circuit thatresponds whether the power storage device is in a charging state or anon-charging state to the power feeder that supplies an electromagneticwave for charging the battery; therefore, when charging of the powerstorage device is completed or the charging thereof is interrupted dueto some cause, unnecessary supply of electric power by anelectromagnetic wave can be stopped. Moreover, the power storage deviceis provided with the circuit that responds to the power feeder whetherthe power storage device is in a charging state or a non-charging state,so that the circuit can inform that the plurality of power storagedevices is charged by the power feeder, and a power storage device to becharged can be selected to perform charging. That is, even when chargingof a plurality of power storage devices is not sufficiently performeddue to electromagnetic wave attenuation, the plurality of power storagedevices can be separately charged. Furthermore, since the power storagedevice of the present invention is provided with the counter circuitinside, the power storage device can receive an electromagnetic wavewith a certain amount or more of electric field intensity, magneticfield intensity, or power flux density even if the average of electricpower is the same.

It is to be noted that the technical components of this embodiment modecan be combined with other technical components in this specification.

Embodiment Mode 2

In this embodiment mode, a structure in which a charging managementcircuit is included in the power storage device described in aboveEmbodiment Mode 1 will be explained with reference to drawings. It is tobe noted that, in the drawings used in this embodiment mode, same partsas those in Embodiment Mode 1 are denoted by the same referencenumerals.

It is to be noted that a “charging management circuit” in thisembodiment mode refers to a circuit that is dedicated to managingcharging/discharging of a battery when using the battery. When using abattery, it is generally necessary to manage the charging/discharging ofthe battery. When charging a battery, it is necessary to performcharging while at the same time monitoring the charged state of thebattery in order to prevent overcharging. For the battery used in thepresent invention, a dedicated circuit is necessary when conductingmanagement of charging.

The power storage device in this embodiment mode will be explained withreference to a block diagram shown in FIG. 11.

A power storage device 100 in FIG. 11 includes an antenna 101, a powersupply portion 102, a charging determination portion 103, a battery 104,and a charging management circuit 1101. Electric power is supplied fromthe power feeder 151 to the power storage device 100, and power storedin the battery 104 inside the power storage device 100 is supplied to aload 152. The power supply portion 102 includes a rectifier circuit 105that rectifies an electromagnetic wave inputted to the antenna 101, acharging control circuit 106 that controls charging of output from therectifier circuit 105 to the battery 104, and a power supply circuit 107for controlling supply of the power charged by the battery 104 to theload 152. The charging determination portion 103 includes a demodulationcircuit 108 for demodulating a signal inputted to the antenna 101, adetermination circuit 109 for determining whether the battery 104 is ina charging state or in a non-charging state and outputting a signal forswitching the charging state and the non-charging state, a countercircuit 110 for counting charging time of the battery 104 and outputtingthe counted time to the determination circuit 109, and a modulationcircuit 111 for modulating a signal to be outputted to an externalportion in accordance with the charging state or the non-charging statedetermined by the determination circuit 109. It is to be noted that thestructure shown in FIG. 11 differs from the structure in FIG. 1 ofEmbodiment Mode 1 in that the charging management circuit 1101 isprovided between the charging control circuit 106 and the battery 104.Therefore, in this embodiment mode, explanation will be given for thecharging management circuit 1101 and the explanation given in EmbodimentMode 1 will be used for other structures.

Next, a structure of the charging management circuit 1101 in thisembodiment mode will be explained with reference to FIG. 12.

The charging management circuit 1101 shown in FIG. 12 includes a switch1201 and a charging amount control circuit 1202. The charging amountcircuit 1202 controls on and off of the switch 1201.

The charging management circuit described here is just an example, andthe present invention may employ another structure without being limitedto this structure. In addition, transistors included in a circuit shownin a circuit diagram of FIG. 13, which are described below, may be anyof thin film transistors, transistors using a single crystal substrate,or organic transistors.

FIG. 13 is a detailed diagram of the block diagram shown in FIG. 12. Theoperation of the circuit is explained below.

In the structure shown in FIG. 13, each of the switch 1201 and thecharging amount control circuit 1202 uses a high potential power supplyline 7526 and a low potential power supply line 7527 as power supplylines. In FIG. 13, the low potential power supply line 7527 is used as aGND line. It is to be noted that the potential of the low potentialpower supply line 7527 is not limited to GND and may be a differentpotential.

The switch 1201 includes a transmission gate 7515 and inverters 7513 and7514, and controls, by an input signal of the inverter 7514, whether tosupply an output signal of the charging control circuit 106 to thebattery 104. The switch 1201 is not limited to this structure and mayemploy another structure.

The charging amount control circuit 1202 includes transistors 7516 to7524 and a resistor 7525. A current flows into the transistors 7523 and7524 from the high potential power supply line 7526 through a resistor7525, so that the transistors 7523 and 7524 are turned on. Thetransistors 7518 to 7522 form a differential comparator. When the gatepotential of the transistor 7520 is lower than the gate potential of thetransistor 7521, the drain potential of the transistor 7518 has almostthe same value as the potential of the high potential power supply line7526, whereas when the gate potential of the transistor 7520 is higherthan the gate potential of the transistor 7521, the drain potential ofthe transistor 7518 has almost the same value as the source potential ofthe transistor 7520.

When the drain potential of the transistor 7518 has almost the samevalue as the potential of the high potential power supply line 7526, thecharging amount control circuit 1202 outputs a low potential signalthrough a buffer including the transistors 7516 and 7517.

When the drain potential of the transistor 7518 has almost the samevalue as the source potential of the transistor 7520, the chargingamount control circuit 1202 outputs a high potential signal through thebuffer including the transistors 7516 and 7517.

When the charging amount control circuit 1202 outputs a low-levelpotential, current is supplied to the battery through the switch 1201.Meanwhile, when the charging amount control circuit 1202 outputs ahigh-level potential, the switch 1201 is turned off and an output signalof the charging control circuit 106 is not supplied to the battery 104.

A gate of the transistor 7520 is connected to the battery 104;therefore, charging stops when the battery 104 is charged and thepotential of the battery exceeds the threshold value of the comparatorof the charging amount control circuit 1202. Although the thresholdvalue of the comparator in this embodiment mode is set at the gatepotential of the transistor 7523, a different potential may be setwithout limitation to this value. In general, the set potential isappropriately determined in accordance with the intended use and theperformance of the battery.

As described above, the structure of the charging management circuit tothe battery is explained in this embodiment mode; however, the presentinvention is not limited to this structure.

With the above structure, the power storage device of the presentinvention can additionally have a function of managing charging of thebattery 104 in the power storage device 100. In addition, the powerstorage device of the present invention employs the structure with thepower storage means; therefore, electric power can be supplied to theload without checking remaining capacity of the battery or changingbatteries with deterioration over time of the battery for drive powersupply voltage. In addition, the power storage device of the presentinvention is provided with the circuit that responds to the power feederthat supplies an electromagnetic wave for charging the battery whetherthe power storage device is in a charging state or a non-charging state;therefore, when charging of the power storage device is completed or thecharging thereof is interrupted due to some cause, unnecessary supply ofelectric power by an electromagnetic wave can be stopped. Moreover, thepower storage device is provided with the circuit that responds to thepower feeder whether the power storage device is in a charging state ora non-charging state, so that the circuit can inform that a plurality ofpower storage devices is charged by the power feeder, and a powerstorage device to be charged can be selected to perform charging. Thatis, even when charging of a plurality of power storage devices is notsufficiently performed due to electromagnetic wave attenuation, theplurality of power storage devices can be separately charged.Furthermore, since the power storage device of the present invention isprovided with the counter circuit inside, the power storage device canreceive an electromagnetic wave with a certain amount or more ofelectric field intensity, magnetic field intensity, or power fluxdensity even if the average of electric power is the same.

It is to be noted that the technical components of this embodiment modecan be combined with other technical components in this specification.

Embodiment Mode 3

In this embodiment mode, a structure in which a signal processingcircuit is provided as a load in the power storage device described inabove Embodiment Mode 1 will be explained with reference to a drawing.It is to be noted that, in some cases, in the drawing used in thisembodiment mode, same parts as those in Embodiment Mode 1 are denoted bythe same reference numerals.

One structural example of a power storage device of the presentinvention in this embodiment mode will be explained with reference to ablock diagram shown in FIG. 14. It is to be noted that, in thisembodiment mode, a signal processing circuit is included in the powerstorage device. Therefore, in this embodiment mode, the case in whichthe power storage device is used as a semiconductor device and thesemiconductor device is used as an RFID will be explained.

A semiconductor device 1400 in FIG. 14 includes an antenna 101, a powersupply portion 102, a charging determination portion 103, a battery 104,and a signal processing circuit 1401. Electric power is supplied to thesemiconductor device 1400 from a reader/writer 1451, and electric powerstored in the battery 104 inside the semiconductor device 1400 issupplied to the signal processing circuit 1401. The power supply portion102 includes a rectifier circuit 105 that rectifies an electromagneticwave inputted to the antenna 101, a charging control circuit 106 thatcontrols charging of output from the rectifier circuit 105 to thebattery 104, and a power supply circuit 107 for controlling supply ofthe electric power charged by the battery 104 to the load 152. Thecharging determination portion 103 includes a demodulation circuit 108for demodulating a signal inputted to the antenna 101, a determinationcircuit 109 for determining whether the battery 104 is in a chargingstate or a non-charging state in accordance with the signal inputtedfrom the antenna 101 and outputting a signal that switches the chargingstate and the non-charging state, a counter circuit 110 for countingcharging time of the battery 104 and outputting the counted time to thedetermination circuit 109, and a modulation circuit for modulating asignal to be outputted to an external portion in accordance with thecharging state or the non-charging state determined by the determinationcircuit 109. The signal processing circuit 1401 includes an amplifier1406 (also referred to as an amplifier circuit), a demodulation circuit1405, a logic circuit 1407, a memory control circuit 1409, a memorycircuit 1409, a logic circuit 1410, an amplifier 1411, and a modulationcircuit 1412. It is to be noted that the structure in FIG. 14 differsfrom the structure in FIG. 1 of Embodiment Mode 1 in that the powerfeeder is replaced with the reader/writer 1451, and the signalprocessing circuit 1401 is connected to the power supply circuit 107.Therefore, in this embodiment mode, an explanation is given for thesignal processing circuit 1401 and the explanation given in EmbodimentMode 1 is used for another structure.

In the signal processing circuit 1401, a communication signaltransmitted from the reader/writer 1451 and received by the antenna 101is inputted to the demodulation circuit 1405 and the amplifier 1406.Communication signals of 13.56 MHz, 915 MHz, and the like are usuallytransmitted after being processed using ASK modulation, PSK modulation,or the like. Here, in FIG. 14, an example of a communication signal of13.56 MHz carrier is shown. In FIG. 14, when a communication signal hasa 13.56 MHz carrier, an electromagnetic wave from the reader/writer,which is for charging the battery 104 desirably, has the same frequencyas the communication signal. It is to be noted that a signal forcharging and a signal for communication are made in the same frequencyband, so that the antenna 101 can be commonly used. The antenna iscommonly used, whereby the size of the semiconductor device can bereduced.

In FIG. 14, a clock signal that is a reference is needed for processinga signal, and a 13.56 MHz carrier is used as a clock here. The amplifier1406 amplifies the 13.56 MHz carrier and supplies it to the logiccircuit 1407 as the clock. The ASK modulated communication signal or thePSK modulated communication signal is demodulated by the demodulationcircuit 1405. The signal which has been demodulated is also transmittedto the logic circuit 1407 to be analyzed. The signal analyzed by thelogic circuit 1407 is transmitted to the memory control circuit 1408,and in accordance with the signal, the memory control circuit 1408controls the memory circuit 1409, extracts data stored in the memorycircuit 1409, and transmits the data to the logic circuit 1410. Thesignal stored in the memory circuit 1409 is encoded by the logic circuit1410 and then amplified by the amplifier 1411, so that the carrier ismodulated by the modulation circuit 1412 with the signal.

Here, power supply voltage in FIG. 14 is supplied by the battery 104through the power supply circuit 107. The power supply circuit 107supplies power to the amplifier 1406, the demodulation circuit 1405, thelogic circuit 1407, the memory control circuit 1408, the memory circuit1409, the logic circuit 1410, the amplifier circuit 1411, the modulationcircuit 1412, and the like. In such a manner, the RFID of thesemiconductor device 1400 operates.

With the above-described structure, the semiconductor device of thepresent invention can additionally have a function dedicated toprocessing of a signal with an external portion by the signal processingcircuit. In addition, the power storage device of the present inventionemploys the structure with the power storage means; therefore, electricpower can be supplied to the load without checking remaining capacity ofthe battery or changing batteries with deterioration over time of thebattery for drive power supply voltage. In addition, the power storagedevice of the present invention is provided with the circuit thatresponds to the power feeder that supplies an electromagnetic wave forcharging the battery whether the power storage device is in a chargingstate or a non-charging state; therefore, when charging of the powerstorage device is completed or the charging thereof is interrupted dueto some cause, unnecessary supply of electric power by anelectromagnetic wave can be stopped. Moreover, the power storage deviceis provided with the circuit that responds to the power feeder whetherthe power storage device is in a charging state or a non-charging state,so that the circuit can inform that a plurality of power storage devicesis charged by the power feeder, and a power storage device to be chargedcan be selected to perform charging. That is, even when charging of aplurality of power storage devices is not sufficiently performed due toelectromagnetic wave attenuation, the plurality of power storage devicescan be separately charged. Furthermore, since the power storage deviceof the present invention is provided with the counter circuit inside,the power storage device can receive an electromagnetic wave with acertain amount or more of electric field intensity, magnetic fieldintensity, or power flux density even if the average of electric poweris the same.

It is to be noted that the technical components of this embodiment modecan be combined with other technical components in this specification.

Embodiment 1

In this embodiment, an example of a battery in the power storage deviceof the present invention will be explained. In this specification, a“battery” refers to a battery that can restore its continuous use timeby being charged. It is preferable to use a battery with a sheet-likeform as the battery. For example, reduction in size is possible with theuse of a lithium battery, preferably a lithium polymer battery that usesa gel electrolyte, a lithium ion battery, or the like. Needless to say,any battery may be used as long as it is chargeable, and a battery thatis chargeable and dischargeable, such as a nickel metal hydride batteryor a nickel cadmium battery may be used. Alternatively, a high-capacitycapacitor or the like can be used.

In this embodiment, a lithium ion battery is explained as an example ofthe battery. A lithium ion battery is widely used because of itsadvantageous properties in that it has no memory effects and candischarge a large amount of current unlike a nickel-cadmium battery, alead battery, and the like. In recent years, research has been focusedon reduction in thickness of a lithium battery, and there has been athin lithium ion battery that is formed with a thickness of 1 μm toseveral μm (hereinafter referred to as a thin-film secondary battery).When such a thin-film secondary battery is attached to an RFID or thelike, the battery can be utilized as a flexible battery.

FIG. 15 illustrates an example of a thin-film secondary battery that canbe used as the battery of the present invention. An example shown inFIG. 15 is an example of a cross section of a thin-film lithium ionbattery.

A stacked structure in FIG. 15 is explained. A current-collecting thinfilm 7102 to serve as an electrode is formed over a substrate 7101 inFIG. 15. It is necessary that current-collecting thin film 7102 has highadhesion to a negative electrode active material layer 7103 and also haslow resistance. For example, aluminum, copper, nickel, vanadium, or thelike can be used. Next, the negative electrode active material layer7103 is formed over the current-collecting thin film 7102. In general,vanadium oxide (V₂O₅) or the like is used. Next, a solid electrolytelayer 7104 is formed over the negative electrode active material layer7103. In general, lithium phosphate (Li₃PO₄) or the like is used. Next,a positive electrode active material layer 7105 is formed over the solidelectrolyte layer 7104. In general, lithium manganate (LiMn₂O₄) or thelike is used. Lithium cobaltate (LiCoO₂) or lithium nickel oxide(LiNiO₂) may also be used. Next, a current-collecting thin film 7106 toserve as an electrode is formed over the positive electrode activematerial layer 7105. It is necessary that current-collecting thin film7106 has high adhesion to the positive electrode active material layer7105 and also has low resistance. For example, aluminum, copper, nickel,vanadium, or the like can be used.

It is to be noted that each of the above-described thin layers of thecurrent-collecting thin film 7102, the negative electrode activematerial layer 7103, the solid electrolyte layer 7104, the positiveelectrode active material layer 7105, and the current-collecting thinfilm 7106 may be formed by a sputtering technique or a vapor-depositiontechnique. In addition, each thickness of the current-collecting thinfilm 7102, the negative electrode active material layer 7103, the solidelectrolyte layer 7104, the positive electrode active material layer7105, and the current-collecting thin film 7106 is desirably 0.1 to 3μm.

Next, the operation in charging and discharging the battery isexplained. In charging the battery, lithium ions are desorbed from thepositive electrode active material layer. Then, the lithium ions areabsorbed into the negative electrode active material layer through thesolid electrolyte layer. At this time, electrons are released to outsidefrom the positive electrode active material layer.

In discharging the battery, on the other hand, lithium ions are desorbedfrom the negative electrode active material layer. Then, the lithiumions are absorbed into the positive electrode active material layerthrough the solid electrolyte layer. At this time, electrons arereleased to outside from the negative electrode active material layer.The thin-film secondary battery operates in this manner.

It is to be noted that it is preferable to stack another set of thinlayers of the current-collecting thin film 7102, the negative electrodeactive material layer 7103, the solid electrolyte layer 7104, thepositive electrode active material layer 7105, and thecurrent-collecting thin film 7106, because charging and discharging witha large amount of electric power become possible.

A thin-film secondary battery is formed in the above manner, so that abattery in a sheet-form that is chargeable and dischargeable can beprovided.

This embodiment can be implemented in combination with the technicalcomponents of the above-described embodiment modes and other embodiment.That is, the power storage device of the present invention employs thestructure with the power storage means; therefore, electric power can besupplied to the load without checking remaining capacity of the batteryor changing batteries with deterioration over time of the battery fordrive power supply voltage. In addition, the power storage device of thepresent invention is provided with the circuit that responds to thepower feeder that supplies an electromagnetic wave for charging thebattery whether the power storage device is in a charging state or anon-charging state; therefore, when charging of the power storage deviceis completed or the charging thereof is interrupted due to some cause,unnecessary supply of electric power by an electromagnetic wave can bestopped. Moreover, the power storage device is provided with the circuitthat responds to the power feeder whether the power storage device is ina charging state or a non-charging state, so that the circuit can informthat a plurality of power storage devices is charged by the powerfeeder, and a power storage device to be charged can be selected toperform charging. That is, even when charging of a plurality of powerstorage devices is not sufficiently performed due to electromagneticwave attenuation, the plurality of power storage devices can beseparately charged. Furthermore, since the power storage device of thepresent invention is provided with the counter circuit inside, the powerstorage device can receive an electromagnetic wave with a certain amountor more of electric field intensity, magnetic field intensity, or powerflux density even if the average of electric power is the same.

Embodiment 2

An example of a method for manufacturing the power storage device shownin the above-described embodiment modes will be explained with referenceto drawings. In this embodiment, a structure in which an antenna, apower supply portion, a charging determination portion, and a batteryare formed over the same substrate will be explained. It is to be notedthat when an antenna, a power supply portion, a charging determinationportion, and a battery are formed over the same substrate, and also whenthin film transistors are used as transistors included in the powersupply portion and a charge determination portion, reduction in size ofthe power storage device can be achieved, which is advantageous. Inaddition, in this embodiment, an example will be explained, in which thethin-film secondary battery explained in the preceding embodiment isused as the battery included in the power supply portion.

First, a peeling layer 1303 is formed over one surface of a substrate1301 with an insulating film 1302 interposed therebetween, and then aninsulating film 1304 functioning as a base film and a semiconductor film(e.g., a film containing amorphous silicon) 1305 are formed thereover(see FIG. 18A). It is to be noted that the insulating film 1302, thepeeling layer 1303, the insulating film 1304, and the semiconductor film1305 can be formed consecutively.

The substrate 1301 is selected from a glass substrate, a quartzsubstrate, a metal substrate (e.g., a stainless steel substrate), aceramic substrate, a semiconductor substrate such as a Si substrate, orthe like. Alternatively, a plastic substrate made of polyethyleneterephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone(PES), acrylic, or the like can be used. In a step shown in FIG. 18A,although the peeling layer 1303 is provided over the entire surface ofthe substrate 1301 with the insulating film 1302 interposed therebetweenthe peeling layer 1303 can also be selectively provided byphotolithography after being provided over the entire surface of thesubstrate 1301.

The insulating films 1302 and 1304 are formed using an insulatingmaterial such as silicon oxide, silicon nitride, silicon oxynitride(SiO_(x)N_(y), where x>y>0), or silicon nitride oxide (SiN_(x)O_(y),where x>y>0) by a CVD method, a sputtering method, or the like. Forexample, when each of the insulating films 1302 and 1304 is formed tohave a two-layer structure, a silicon nitride oxide film may be formedas a first insulating film and a silicon oxynitride film may be formedas a second insulating film. In addition, a silicon nitride film may beformed as a first insulating film and a silicon oxide film may be formedas a second insulating film. The insulating film 1302 functions as ablocking layer which prevents an impurity element contained in thesubstrate 1301 from being mixed into the peeling layer 1303 or elementsformed thereover. The insulating film 1304 functions as a blocking layerwhich prevents an impurity element contained in the substrate 1301 orthe peeling layer 1303 from being mixed into elements formed over theinsulating film 1304. In this manner, providing the insulating films1302 and 1304 which function as the blocking layers can prevent adverseeffects on the elements formed over the peeling layer 1303 or theinsulating film 1304, which would otherwise be caused by an alkali metalsuch as Na or an alkaline earth metal contained in the substrate 1301 orby the impurity element contained in the peeling layer 1303. It is to benoted that when quartz is used for the substrate 1301, for example, theinsulating films 1302 and 1304 may be omitted.

The peeling layer 1303 may be formed using a metal film, a stackedstructure of a metal film and a metal oxide film, or the like. As ametal film, either a single layer or stacked layers are formed using anelement selected from tungsten (W), molybdenum (Mo), titanium (Ti),tantalum (Ta), niobium (Nb), nickel (Ni), cobalt (Co), zirconium (Zr),zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os),and iridium (Ir), or an alloy material or a compound material containingthe element as its main component. In addition, such materials can beformed by a sputtering method, various CVD methods such as a plasma CVDmethod, or the like. A stacked structure or a metal film and a metaloxide film can be obtained by the steps of forming the above-describedmetal film, applying plasma treatment thereto under an oxygen atmosphereor an N₂O atmosphere or applying heat treatment thereto under an oxygenatmosphere or an N₂O atmosphere, and thereby forming oxide or oxynitrideof the metal film on the surface of the metal film. For example, when atungsten film is provided as a metal film by a sputtering method, a CVDmethod, or the like, a metal oxide film formed of tungsten oxide can beformed on the surface of the tungsten film by application of plasmatreatment to the tungsten film. In that case, the tungsten oxide can berepresented by WO_(x) where x is in the range of 2 to 3. For example,there are cases where x is 2 (WO₂), x is 2.5 (W₂O₅), x is 2.75 (W₄O₁₁),x is 3 (WO₃), and the like. When forming tungsten oxide, there is noparticular limitation on the value of x, and thus, which of the aboveoxides is to be formed may be determined base on the etching rate of thelike. In addition, after a metal film (e.g., tungsten) is formed, aninsulating film formed of silicon oxide (SiO₂) or the like may be formedover the metal film by a sputtering method, and also metal oxide (e.g.,tungsten oxide over tungsten) may be formed over the metal film.Moreover, high-density-plasma treatment may be applied as the plasmatreatment, for example. Besides, metal nitride or metal oxynitride mayalso be formed. In that case, plasma treatment or heat treatment may beapplied to the metal film under a nitrogen atmosphere or an atmospherecontaining nitrogen and oxygen.

The amorphous semiconductor film 1305 is formed with a thickness of 25to 200 nm (preferably, 30 to 150 nm) by a sputtering method, an LPCVDmethod, a plasma CVD method, or the like.

Next, the amorphous semiconductor film 1305 is crystallized by laserlight irradiation. It is to be noted that the crystallization of theamorphous semiconductor film 1305 may also be performed by a methodcombining the laser crystallization with a thermal crystallizationmethod using RTA or an annealing furnace or with a thermalcrystallization method using a metal element that promotes thecrystallization. After that, the crystalline semiconductor film isetched into a desired shape, whereby crystalline semiconductor films1305 a to 1305 f are formed. Then, a gate insulating film 1306 is formedso as to cover the semiconductor films 1305 a to 1305 f (see FIG. 18B).

The gate insulating film 1306 is formed using an insulating materialsuch as silicon oxide, silicon nitride, silicon oxynitride(SiO_(x)N_(y), where x>y>0), or silicon nitride oxide (SiN_(x)O_(y),where x>y>0) by a CVD method, a sputtering method, or the like. Forexample, when the gate insulating film 1306 is formed to have atwo-layer structure, it is preferable to form a silicon oxynitride filmas a first insulating film and form a silicon nitride oxide film as asecond insulating film. Alternatively, it is also preferable to form asilicon oxide film as a first insulating film and form a silicon nitridefilm as a second insulating film.

An example of a formation step of the crystalline semiconductor films1305 a to 1305 f is briefly explained below. First, an amorphoussemiconductor film with a thickness of 50 to 60 nm is formed by a plasmaCVD method. Then, a solution containing nickel which is a metal elementthat promotes crystallization is retained on the amorphous semiconductorfilm, which is followed by dehydrogenation treatment (500° C. for onehour) and thermal crystallization treatment (550° C. for four hours).Thus, a crystalline semiconductor film is formed. Thereafter, thecrystalline semiconductor film is irradiated with laser light by aphotolithography method and etched, whereby the crystallinesemiconductor films 1305 a to 1305 f are formed. It is to be noted thatcrystallization of the amorphous semiconductor film may be performedonly by laser light irradiation, not by thermal crystallization whichuses a metal element that promotes crystallization.

As a laser oscillator used for crystallization, either a continuous wavelaser (a CW laser) or a pulsed laser can be used. As a laser that can beused here, there are gas lasers such as an Ar laser, a Kr laser, and anexcimer laser; a laser in which single-crystalline YAG, YVO₄, forsterite(Mg₂SiO₄), YAlO₃, or GdVO₄ or polycrystalline (ceramic) YAG, Y₂O₃, YVO₄,YAlO₃, or GdVO₄ is doped with one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm,and Ta as a dopant; a glass laser; a ruby laser; an alexandrite laser; aTi:sapphire laser; a copper vapor laser; and a gold vapor laser. Whenirradiation is performed with the fundamental wave of such a laser beamor the second to fourth harmonics of the fundamental wave, crystals witha large grain size can be obtained. For example, the second harmonic(532 nm) or the third harmonic (355 nm) of an Nd:YVO₄ laser (thefundamental wave of 1064 nm) can be used. In this case, a laser powerdensity of approximately 0.01 to 100 MW/cm² (preferably, 0.1 to 10MW/cm²) is needed, and irradiation is performed with a scanning rate ofapproximately 10 to 2000 cm/sec. It is to be noted that the laser inwhich single crystal YAG, YVO₄, forsterite (Mg₂SiO₄), YAlO₃, or GdVO₄ orpolycrystalline (ceramic) YAG, Y₂O₃, YVO₄, YAlO₃, or GdVO₄ is doped withone or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta as a dopant; an Ar ionlaser, or a Ti:sapphire laser can be used as a CW laser, whereas it canalso be used as pulsed laser with a repetition rate of 10 MHz or more bya Q-switch operation, mode locking, or the like. When a laser beam witha repetition rate of 10 MHz or more is used, a semiconductor film isirradiated with the next pulse during the period in which thesemiconductor film is melted by the previous laser and solidified.Therefore, unlike the case of using a pulsed laser with a low repetitionrate, a solid-liquid interface in the semiconductor film can becontinuously moved. Thus, crystal grains which have grown continuouslyin the scanning direction can be obtained.

The gate insulating film 1306 may be formed by oxidization ornitridation of the surfaces of the semiconductor films 1305 a to 1305 fby the above-described high-density plasma treatment. For example,plasma treatment with a mixed gas of a rare gas such as He, Ar, Kr, orXe, and oxygen, nitrogen oxide (NO₂), ammonia, nitrogen, or hydrogen isused. When plasma is excited by the introduction of microwaves, plasmawith a low electron temperature and high density can be generated. Withoxygen radicals (which may include OH radicals) or nitrogen radicals(which may include NH radicals) which are generated by the high-densityplasma, the surfaces of the semiconductor films can be oxidized ornitrided.

By such high-density plasma treatment, an insulating film with athickness of 1 to 20 nm, typically 5 to 10 nm, is formed on thesemiconductor films. Since the reaction in this case is a solid-phasereaction, interface state density between the insulating film and thesemiconductor films can be quite low. Since such high-density plasmatreatment directly oxidizes (or nitrides) the semiconductor films(crystalline silicon or polycrystalline silicon), the insulating filmcan be formed with extremely little unevenness, which is ideal. Inaddition, since crystal grain boundaries of crystalline silicon are notstrongly oxidized, an excellent state is obtained. That is, by thesolid-phase oxidation of the surfaces of the semiconductor films byhigh-density plasma treatment which is described in this embodimentmode, an insulating film with a uniform thickness and low interfacestate density can be formed without excessive oxidation reaction at thecrystal grain boundaries.

As the gate insulating film, only an insulating film formed byhigh-density plasma treatment may be used, or a stacked layer which isobtained by deposition of an insulating film such as silicon oxide,silicon oxynitride, or silicon nitride on the insulating film by a CVDmethod using plasma or thermal reaction. In either case, a transistorwhich includes an insulating film formed by high-density plasmatreatment in a part or the whole of its gate insulating film can havesmall characteristic variations.

In addition, the semiconductor films 1305 a to 1305 f, which areobtained by irradiation of a semiconductor film with a continuous wavelaser beam oscillated with a repetition rate of 10 MHz or more andscanning of the semiconductor film in one direction to crystallize thesemiconductor film, have a characteristic in that their crystals grow inthe beam scanning direction. A transistor is arranged so that itschannel length direction (direction in which carriers move when achannel formation region is formed) is aligned with the scanningdirection, and the above-described gate insulating film is combined withthe semiconductor film, whereby a thin film transistor (TFTs) with highelectron field effect mobility and few variations in characteristics canbe obtained.

Next, a first conductive film and a second conductive film are stackedover the gate insulating film 1306. Here, the first conductive film isformed to a thickness of 20 to 100 nm by a CVD method, a sputteringmethod, or the like. The second conductive film is formed to a thicknessof 100 to 400 nm. The first conductive film and the second conductivefilm are formed of an element selected from tantalum (Ta), tungsten (W),titanium (Ti), molybdenum (Mo), aluminum (Al), copper (Cu), chromium(Cr), niobium (Nb), and the like, or an alloy material or a compoundmaterial containing the element as its main component. Alternatively,the first conductive film and the second conductive film are formed of asemiconductor material typified by polycrystalline silicon doped with animpurity element such as phosphorus. As a combination example of thefirst conductive film and the second conductive film, a tantalum nitridefilm and a tungsten film; a tungsten nitride film and a tungsten film; amolybdenum nitride film and a molybdenum film; and the like can begiven. Tungsten and tantalum nitride have high heat resistance.Therefore, after forming the first conductive film and the secondconductive film, thermal treatment for the purpose of heat activationcan be applied thereto. In addition, in the case where a two-layerstructure is not employed, but a three-layer structure is employed, itis preferable to use a stacked structure of a molybdenum film, analuminum film, and a molybdenum film.

Next, a resist mask is formed by photolithography, and etching treatmentfor forming gate electrodes and gate lines is applied. Thus, gateelectrodes 1307 are formed above the semiconductor films 1305 a to 1305f. Here, a stacked structure of a first conductive film 1307 a and asecond conductive film 1307 b is shown as an example of the gateelectrode 1307.

Next, the semiconductor films 1305 a, 1305 b, 1305 d, and 1305 f aredoped with an n-type impurity element at low concentration, using thegate electrodes 1307 as masks by an ion doping method or an ionimplantation method. Then, a resist mask is selectively formed byphotolithography, and the semiconductor films 1305 c and 1305 e aredoped with a p-type impurity element at high concentration. As an n-typeimpurity element, phosphorus (P), arsenic (As), or the like can be used.As a p-type impurity element, boron (B), aluminum (Al), gallium (Ga), orthe like can be used. Here, phosphorus (P) is used as an n-type impurityelement and is selectively introduced into the semiconductor films 1305a, 1305 b, 1305 d, and 1305 f so as to be contained at concentrations of1×10¹⁵ to 1×10¹⁹/cm³. Thus, n-type impurity regions 1308 are formed. Inaddition, boron (B) is used as a p-type impurity element, and isselectively introduced into the semiconductor films 1305 c and 1305 e soas to be contained at concentrations of 1×10¹⁹ to 1×10²⁰/cm³. Thus,n-type impurity regions 1309 are formed (see FIG. 18C).

Subsequently, an insulating film is formed so as to cover the gateinsulating film 1306 and the gate electrodes 1307. The insulating filmis formed to have either a single layer or a stacked layer of a filmcontaining an inorganic material such as silicon, silicon oxide, orsilicon nitride, or a film containing an organic material such as anorganic resin by a plasma CVD method, a sputtering method, or the like.Next, the insulating film is selectively etched by anisotropic etching(mainly in the perpendicular direction), so that insulating films 1310(also referred to as sidewalls) which is in contact with the sidesurfaces of the gate electrodes 1307 are formed. The insulating films1310 are used as doping masks for forming LDD (Lightly Doped Drain)regions.

Next, the semiconductor films 1305 a, 1305 b, 1305 d, and 1305 f aredoped with an n-type impurity element at high concentration, using thegate electrodes 1307 and the insulating films 1310 as masks. Thus,n-type impurity regions 1311 are formed. Here, phosphorus (P) is used asan n-type impurity element, and is selectively introduced into thesemiconductor films 1305 a, 1305 b, 1305 d, and 1305 f so as to becontained at concentrations of 1×10¹⁹ to 1×10²⁰/cm³. Thus, the n-typeimpurity regions 1311 with higher concentration of impurity than that ofthe impurity regions 1308 are formed.

Through the above steps, n-channel transistors 1300 a, 1300 b, 1300 d,and 1300 f, and p-channel thin film transistors 1300 c and 1300 e areformed (see FIG. 18D).

In the n-channel thin film transistor 1300 a, a channel formation regionis formed in a region of the semiconductor film 1305 a which overlapswith the gate electrode 1307; the impurity region 1311 which forms asource region or a drain region is formed in a region of thesemiconductor film 1305 a which does not overlap with the gate electrode1307 and the insulating film 1310; and a low concentration impurityregion (LDD region) is formed in a region of the semiconductor film 1305a which overlaps with the insulating film 1310 and between the channelformation region and the impurity region 1311. Similarly, channelformation regions, low concentration impurity regions, and the impurityregions 1311 are formed in the n-channel thin film transistors 1300 b,1300 d, and 1300 f.

In the p-channel thin film transistor 1300 c, a channel formation regionis formed in a region of the semiconductor film 1305 c which overlapswith the gate electrode 1307, and the impurity region 1309 which forms asource region or a drain region is formed in a region of thesemiconductor film 1305 c which does not overlap with the gate electrode1307. Similarly, a channel formation region and the impurity region 1309are formed in the p-channel thin film transistor 1300 e. Here, althoughLDD regions are not formed in the p-channel thin film transistors 1300 cand 1300 e, LDD regions may be provided in the p-channel thin filmtransistors or a structure without LDD regions may be applied to then-channel thin film transistors.

Next, an insulating film with a single layer or stacked layers is formedso as to cover the semiconductor films 1305 a to 1305 f, the gateelectrodes 1307, and the like. Then, conductive films 1313 electricallyconnected to the impurity regions 1309 and 1311 which form the sourceand drain regions of the thin film transistors 1300 a to 1300 f areformed over the insulating film (see FIG. 19A). The insulating film isformed of a single layer or a stacked layer, using an inorganic materialsuch as silicon oxide or silicon nitride, an organic material such aspolyimide, polyamide, benzocyclobutene, acrylic, or epoxy, a siloxanematerial, or the like by a CVD method, a sputtering method, an SOGmethod, a droplet discharging method, a screen printing method, or thelike. Here, the insulating film is formed to have two layers, and asilicon nitride oxide film is formed as a first insulating film 1312 aand a silicon oxynitride film is formed as a second insulating film 1312b. In addition, the conductive films 1313 can form the source and drainelectrodes of the thin film transistors 1300 a o 1300 f.

It is to be noted that before the insulating films 1312 a and 1312 b areformed or after one or both of them is/are formed, heat treatment ispreferably applied for recovery of the crystallinity of thesemiconductor films, activation of the impurity element which has beenadded into the semiconductor films, or hydrogenation of thesemiconductor films. As the heat treatment, thermal annealing, laserannealing, RTA, or the like is preferably applied.

The conductive films 1313 are formed of a single layer or a stackedlayer of an element selected from aluminum (Al), tungsten (W), titanium(Ti), tantalum (Ta), molybdenum (Mo), nickel (Ni), platinum (Pt), copper(Cu), gold (Au), silver (Ag), manganese (Mn), neodymium (Nd), carbon(C), and silicon (Si), or an alloy material or a compound materialcontaining the element as its main component. An alloy materialcontaining aluminum as its main component corresponds to, for example, amaterial which contains aluminum as its main component and also containsnickel, or a material which contains aluminum as its main component andalso contains nickel and one or both of carbon and silicon. Theconductive films 1313 are preferably formed to have a stacked structureof a barrier film, an aluminum-silicon (Al—Si) film, and a barrier filmor a stacked structure of a barrier film, an aluminum silicon (Al—Si)film, a titanium nitride film, and a barrier film. It is to be notedthat the “barrier film” corresponds to a thin film formed of titanium,titanium nitride, molybdenum, or molybdenum nitride. Aluminum andaluminum silicon are the most suitable material for forming theconductive films 1313 because they have low resistance value and areinexpensive. When barrier layers are provided as the top layer and thebottom layer, generation of hillocks of aluminum or aluminum silicon canbe prevented. In addition, when a barrier film formed of titanium whichis an element having a high reducing property is formed, even when thereis a thin natural oxide film formed on the crystalline semiconductorfilm, the natural oxide film can be chemically reduced, and a favorablecontact between the conductive film 1313 and the crystallinesemiconductor film can be obtained.

Next, an insulating film 1314 is formed so as to cover the conductivefilms 1313, and conductive films 1315 a and 1315 b electricallyconnected to the conductive films 1313 which form the source electrodeor the drain electrode of the thin film transistors 1300 a and 1300 fare formed. In addition, a conductive film 1316 electrically connectedto the conductive film 1313 which forms the source electrode or drainelectrode of the thin film transistor 1300 b is formed. It is to benoted that the conductive films 1315 a and 1315 b and the conductivefilm 1316 may be formed using the same material. The conductive films1315 a and 1315 b and the conductive film 1316 may be formed using anyof the above-described material which has been described for theconductive film 1313.

Next, a conductive film 1317 functioning as an antenna is formed so asto be electrically connected to the conductive film 1316 (see FIG. 19B).

The insulating film 1314 can be formed of a single layer or a stackedlayer of an insulating film containing oxygen or nitrogen such assilicon oxide (SiO_(x)), silicon nitride (SiN_(x)), silicon oxynitride(SiO_(x)N_(y) where x>y>0), or silicon nitride oxide (SiN_(x)O_(y) wherex>y>0); a film containing carbon such as DLC (Diamond-Like Carbon); anorganic material such as epoxy, polyimide, polyamide, polyvinyl phenol,benzocyclobutene, or acrylic; or a siloxane material such as a siloxaneresin. It is to be noted that a siloxane material corresponds to amaterial having a bond of Si—O—Si. Siloxane has a skeleton structurewith the bond of silicon (Si) and oxygen (O). As a substituent ofsiloxane, an organic group containing at least hydrogen (e.g., an alkylgroup or aromatic hydrocarbon) is used. Alternatively, a fluoro groupmay be used as the substituent. Further alternatively, both a fluorogroup and an organic group containing at least hydrogen may be used asthe substituent.

The conductive film 1317 can be formed of a conductive material by a CVDmethod, a sputtering method, a printing method such as screen printingor gravure printing, a droplet discharging method, a dispenser method, aplating method, or the like. The conductive film 1317 is formed of asingle layer or a stacked layer of an element selected from aluminum(Al), titanium (Ti), silver (Ag), copper (Cu), gold (Au), platinum (Pt),nickel (Ni), palladium (Pd), tantalum (Ta), and molybdenum (Mo), or analloy material or a compound material containing the element as its maincomponent.

For example, when the conductive film 1317 functioning as an antenna isformed by a screen printing method, the antenna can be provided byselective printing of a conductive paste in which conductive particleswith a grain diameter of several nm to several tens of μm are dissolvedor dispersed in an organic resin. The conductive particles can be atleast one or more of metal particles selected from silver (Ag), gold(Ag), copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), tantalum(Ta), molybdenum (Mo), titanium (Ti), and the like; fine particles ofsilver halide; and dispersive nanoparticles. In addition, the organicresin included in the conductive paste can be one or more of organicresins which function as a binder, a solvent, a dispersing agent, and acoating material of the metal particles. Typically, an organic resinsuch as an epoxy resin and a silicone resin can be given as examples. Inaddition, it is preferable to form the conductive film by the steps ofproviding a conductive paste and baking it. For example, in the case ofusing fine particles (e.g., a grain diameter of 1 to 100 nm) containingsilver as its main component as a material of the conductive paste, theconductive paste is baked and hardened at temperatures in the range of150 to 300° C., so that the conductive film can be obtained.Alternatively, it is also possible to use fine particles containingsolder or lead-free solder as its main component. In that case, fineparticles with a grain diameter of less than or equal to 20 μm arepreferably used. Solder and lead-free solder have the advantage of lowcost.

The conductive films 1315 a and 1315 b can function as wirings which areelectrically connected to the battery included in the power storagedevice of the present invention in a later step. In addition, in formingthe conductive film 1317 which functions as an antenna, another set ofconductive films may be separately formed so as to be electricallyconnected to the conductive films 1315 a and 1315 b, so that theconductive films can be utilized as the wirings connected to thebattery.

Next, after forming an insulating film 1318 so as to cover theconductive film 1317, layers including the thin film transistors 1300 ato 1300 f, the conductive film 1317, and the like (hereinafter referredto as an “element formation layer 1319”) are peeled off the substrate1301. Here, after forming openings in the element formation layer 1319excluding the region of the thin film transistors 1300 a to 1300 f bylaser light irradiation (e.g., UV light) (see FIG. 19C), the elementformation layer 1319 can be peeled off the substrate 1301 with aphysical force. The peeling layer 1303 may be selectively removed byintroduction of an etchant into the openings before peeling the elementformation layer 1319 off the substrate 1301. As the etchant, a gas or aliquid containing halogen fluoride or an interhalogen compound is used.For example, when chlorine trifluoride (ClF₃) is used as the gascontaining halogen fluoride, the element formation layer 1319 is peeledoff the substrate 1301. It is to be noted that the whole peeling layer1303 is not removed but part thereof may be left. Accordingly, theconsumption of the etchant can be suppressed and process time forremoving the peeling layer can be shortened. In addition, even afterremoving the peeling layer 1301, the element formation layer 1319 can beheld above the substrate 1301. In addition, by reuse of the substrate1301 over which the element formation layer 1319 has been peeled off,cost reduction can be achieved.

The insulating film 1318 can be formed of a single layer or a stackedlayer of an insulating film containing oxygen or nitrogen such assilicon oxide (SiO_(x)), silicon nitride (SiN_(x)), silicon oxynitride(SiO_(x)N_(y) where x>y>0), or silicon nitride oxide (SiN_(x)O_(y) wherex>y>0); a film containing carbon such as DLC (Diamond-Like Carbon); anorganic material such as epoxy, polyimide, polyimide, polyvinyl phenol,benzocyclobutene, or acrylic; or a siloxane material such as a siloxaneresin by a CVD method, a sputtering method, or the like.

In this embodiment, after forming the openings in the element formationlayer 1319 by laser light irradiation, a first seat material 1320 isattached to one surface of the element formation layer 1319 (the surfacewhere the insulating film 1318 is exposed), and then the elementformation layer 1319 is peeled off the substrate 1301 (see FIG. 20A).

Next, a second seat material 1321 is attached to the other surface ofthe element formation layer 1319 (the surface exposed by peeling),followed by one or both of heat treatment and pressurization treatment(see FIG. 20B). As the first seat material 1320 and the second seatmaterial 1321, a hot-melt film or the like can be used.

As the first sheet material 1320 and the second sheet material 1321, afilm on which antistatic treatment for preventing static electricity orthe like has been applied (hereinafter referred to as an antistaticfilm) can be used. As examples of the antistatic film, a film in whichan antistatic material is dispersed in a resin, a film to which anantistatic material is attached, and the like can be given. The filmprovided with an antistatic material can be a film with an antistaticmaterial provided over one of its surfaces, or a film with an antistaticmaterial provided over each of its surfaces. The film with an antistaticmaterial provided over one of its surfaces may be attached to the layerso that the antistatic material is placed on the inner side of the filmor the outer side of the film. The antistatic material may be providedover the entire surface of the film, or over a part of the film. As anantistatic material, a metal, indium tin oxide (ITO), or a surfactantsuch as an amphoteric surfactant, a cationic surfactant, or a nonionicsurfactant can be used. In addition, as an antistatic material, a resinmaterial which contains a cross-linked copolymer having a carboxyl groupand a quaternary ammonium base on its side chain, or the like can beused. Such a material is attached, mixed, or applied to a film, so thatan antistatic film can be formed. The element formation layer is sealedusing the antistatic film, so that the semiconductor elements can beprevented from adverse effects such as external static electricity whendealt with as a commercial product.

It is to be noted that the thin-film secondary battery described inEmbodiment 1 is connected to the conductive films 1315 a and 1315 b, sothat the battery is formed. Connection between the battery and theconductive films 1315 a and 1315 b may be conducted before the elementformation layer 1319 is peeled off the substrate 1301 (at the stageshown in FIG. 19B or FIG. 19C), after the element formation layer 1319is peeled off the substrate 1301 (at the stage shown in FIG. 20A), orafter the element formation layer 1319 is sealed with the first sheetmaterial and the second sheet material (at the stage shown in FIG. 20B).An example where the element formation layer 1319 and the battery areformed to be connected is explained below with reference to FIGS. 21Aand 21B and FIGS. 22A and 22B.

In FIG. 19B, conductive films 1331 a and 1331 b which are electricallyconnected to the conductive films 1315 a and 1315 b, respectively areformed at the same time as the conductive film 1317 which functions asan antenna. Then, the insulating film 1318 is formed so as to cover theconductive films 1317, 1331 a, and 1331 b, followed by formation ofopenings 1332 a and 1332 b so that the surfaces of the conductive films1331 a and 1331 b are exposed. After that, openings are formed in theelement formation layer 1319 by laser light irradiation, and the firstseat material 1332 is attached to one surface of the element formationlayer 1319 (the surface where the insulating film 1318 is exposed), sothat the element formation layer 1319 is peeled off the substrate 1301(see FIG. 21A).

Next, the second seat material 1333 is attached to the other surface ofthe element formation layer 1319 (the surface exposed by peeling), andthe element formation layer 1319 is peeled off the first seat material1332. Therefore, a material with low viscosity is used as the first seatmaterial 1320. Then, conductive films 1334 a and 1334 b which areelectrically connected to the conductive films 1331 a and 1331 brespectively through the openings 1332 a and 1332 b are selectivelyformed (see FIG. 21B).

The conductive films 1334 a and 1334 b are formed of a conductivematerial by a CVD method, a sputtering method, a printing method such asscreen printing or gravure printing, a droplet discharging method, adispenser method, a plating method, or the like. The conductive films1334 a and 1334 b are formed of a single layer or a stacked layer of anelement selected from aluminum (Al), titanium (Ti), silver (Ag), copper(Cu), gold (Au), platinum (Pt), nickel (Ni), palladium (Pd), tantalum(Ta), and molybdenum (Mo), or an alloy material or a compound materialcontaining the element as its main component.

It is to be noted that although the example shown here is the case wherethe conductive films 1334 a and 1334 b are formed after peeling theelement formation layer 1319 off the substrate 1301, the elementformation layer 1319 may be peeled off the substrate 1301 after theformation of the conductive films 1334 a and 1334 b.

Next, in the case where a plurality of elements is formed over thesubstrate, the element formation layer 1319 is cut into individualelements (see FIG. 22A). A laser irradiation apparatus, a dicingapparatus, a scribing apparatus, or the like can be used for thecutting. Here, the plurality of elements formed over one substrate isseparated from one another by laser light irradiation.

Next, the separated elements are electrically connected to the battery(see FIG. 22B). In this embodiment mode, the thin-film secondary batterydescribed in Embodiment 1 is used as the battery, in which acurrent-collecting thin film, a negative electrode active materiallayer, a solid electrolyte layer, a positive electrode active materiallayer, and a current-collecting thin film are sequentially stacked.

Conductive films 1336 a and 1336 b are formed of a conductive materialby a CVD method, a sputtering method, a printing method such as screenprinting or gravure printing, a droplet discharging method, a dispensermethod, a plating method, or the like. The conductive films 1336 a and1336 b are formed of a single layer or a stacked layer of an elementselected from aluminum (Al), titanium (Ti), silver (Ag), copper (Cu),gold (Au), platinum (Pt), nickel (Ni), palladium (Pd), tantalum (Ta),and molybdenum (Mo), or an alloy material or a compound materialcontaining the element as its main component. It is to be noted that theconductive films 1336 a and 1336 b correspond to the current-collectingthin film 7102 described in Embodiment 1. Therefore, it is necessarythat the conductive material has high adhesion to a negative electrodeactive material layer and also has low resistance. In particular,aluminum, copper, nickel, vanadium, or the like is preferably used.

The structure of the thin-film secondary battery is described next. Anegative electrode active material layer 1381 is formed over theconductive film 1336 a. In general, vanadium oxide (V₂O₅) or the like isused. Next, a solid electrolyte layer 1382 is formed over the negativeelectrode active material layer 1381. In general, lithium phosphate(Li₃PO₄) or the like is used. Next, a positive electrode active materiallayer 1383 is formed over the solid electrolyte layer 1382. In general,lithium manganate (LiMn₂O₄) or the like is used. Lithium cobaltate(LiCoO₂) or lithium nickel oxide (LiNiO₂) may also be used. Next, acurrent-collecting thin film 1384 to serve as an electrode is formedover the positive electrode active material layer 1383. It is necessarythat the current-collecting thin film 1384 has high adhesion to thepositive electrode active material layer 1383 and also has lowresistance. For example, aluminum, copper, nickel, vanadium, or the likecan be used.

Each of the above thin layers of the negative electrode active materiallayer 1381, the solid electrolyte layer 1382, the positive electrodeactive material layer 1383, and the current-collecting thin film 1384may be formed by a sputtering technique or a vapor-deposition technique.In addition, the thickness of each layer is preferably 0.1 to 3 μm.

Next, an interlayer film 1385 is formed by application of a resin. Theinterlayer film 1385 is etched to form a contact hole. The interlayerfilm 1385 is not limited to a resin, and other films such as a CVD oxidefilm may be used as well; however, a resin is preferably used in teensof flatness. In addition, the contact hole may be formed without usingetching, but using a photosensitive resin. Next, a wiring layer 1386 isformed over the interlayer film 1385 and connected to the conductivefilm 1334 b. Thus, an electrical connection between the thin-filmsecondary battery and the element formation layer 1319 is secured.

Here, the conductive films 1334 a and 1334 b which are provided in theelement formation layer 1319 are connected to the conductive films 1336a and 1336 b respectively, which serve as the connecting terminals ofthe thin-film secondary battery 1389 which is the battery stacked inadvance. Here, an example is shown in which an electrical connectionbetween the conductive films 1334 a and 1336 a or an electricalconnection between the conductive films 1334 b and 1336 b is performedby pressure bonding with an adhesive material such as an anisotropicconductive film (ACF) or an anisotropic conductive paste (ACP). Theexample shown here is the case where the connection is performed usingconductive particles 1338 included in an adhesive resin 1337.Alternatively, a conductive adhesive such as a silver paste, a copperpaste, or a carbon paste; solder joint; or the like can be used.

It is to be noted that the structure of a transistor can be variouswithout being limited to the specific structure shown in thisembodiment. For example, a multi-gate structure having two or more gateelectrodes may be employed. When a multi-gate structure is employed, astructure in which channel regions are connected in series is provided;therefore, a structure in which a plurality of transistors is connectedin series is provided. When a multi-gate structure is employed, variousadvantages can be obtained in that off-current can be reduced; withstandvoltage of the transistor can be increased, so that the reliability isincreased; and even if drain-source voltage changes when the transistoroperates in the saturation region, a drain-source current does notchange very much, and thus flat characteristics can be obtained. Inaddition, a structure in which gate electrodes are formed above andbelow a channel may also be employed. When a structure in which gateelectrodes are formed above and below a channel is employed, the channelregion is enlarged and the amount of current flowing therethrough can beincreased. Thus, a depletion layer can be easily formed and the S valuecan be decreased. When gate electrodes are formed above and below achannel, a structure in which a plurality of transistors is connected inparallel is provided.

In addition, any of the following structures may be employed: astructure in which a gate electrode is formed above a channel; astructure in which a gate electrode is formed below a channel; astaggered structure; an inversely staggered structure; and a structurein which a channel region is divided into a plurality of regions and thedivided regions are connected in parallel or in series. In addition, achannel (or part thereof) may overlap with a source electrode or a drainelectrode. However, when a structure in which a channel (or partthereof) does not overlap with a source electrode or a drain electrodeis employed, electric charge can be prevented from being accumulated inpart of the channel and an unstable operation can be prevented. Inaddition, an LDD (Lightly Doped Drain) region may be provided. When anLDD region is provided, off-current can be reduced; the withstandvoltage of the transistor can be increased, so that the reliability isincreased; and even if drain-source voltage changes when the transistoroperates in the saturation region, drain-source current does not changevery much, and thus flat characteristics can be obtained.

This embodiment can be implemented in combination with the technicalcomponents of the above-described embodiment modes and other embodiment.That is, the power storage device of the present invention employs thestructure with the power storage means; therefore, electric power can besupplied to the load without checking remaining capacity of the batteryor changing batteries with deterioration over time of the battery fordrive power supply voltage. In addition, the power storage device of thepresent invention is provided with the circuit that responds to thepower feeder that supplies an electromagnetic wave for charging thebattery whether the power storage device is in a charging state or anon-charging state; therefore, when charging of the power storage deviceis completed or the charging thereof is interrupted due to some causes,unnecessary supply of electric power by an electromagnetic wave can bestopped. Moreover, the power storage device is provided with the circuitthat responds to the power feeder whether the power storage device is ina charging state or a non-charging state, so that the circuit can informthat a plurality of power storage devices is charged by the powerfeeder, and a power storage device to be charged can be selected toperform charging. That is, even when charging of a plurality of powerstorage devices is not sufficiently performed due to electromagneticwave attenuation, the plurality of power storage devices can beseparately charged. Furthermore, since the power storage device of thepresent invention is provided with the counter circuit inside, the powerstorage device can receive an electromagnetic wave with a certain amountor more of electric field intensity, magnetic field intensity, or powerflux density even if the average of electric power is the same.

Embodiment 3

An example of a method for manufacturing a power storage devicedescribed in the above embodiment modes will be explained with referenceto drawings. In this embodiment, a structure in which an antenna, apower supply portion, a charging determination portion, and a batteryare formed over the same substrate will be explained. It is to be notedthat when an antenna, a power supply portion, a charging determinationportion, and a battery are formed over a substrate at a time, and alsowhen transistors formed using a single crystal substrate are used as thetransistors included in the power supply portion and the chargingdetermination portion, a power storage device having transistors withfew characteristic variations can be formed, which is preferable. Inaddition, in this embodiment, an example is explained in which thethin-film secondary battery described in the above-described embodimentis used as the battery included in the power supply portion.

First, element separation regions 2304 and 2306 (hereinafter simplyreferred to as regions 2304 and 2306) are formed in a semiconductorsubstrate 2300 (see FIG. 23A). The regions 2304 and 2306 provided in thesemiconductor substrate 2300 are insulated from each other by aninsulating film (also referred to as a field oxide film) 2302. Theexample shown here is the case where a single crystal Si substratehaving n-type conductivity is used as the semiconductor substrate 2300,and a p well 2307 is formed in the region 2306 of the semiconductorsubstrate 2300.

Any substrate can be used as the substrate 2300 as long as it is asemiconductor substrate. For example, a single crystal Si substratehaving n-type or p-type conductivity, a compound semiconductor substrate(e.g., a GaAs substrate, an InP substrate, a GaN substrate, a SiCsubstrate, a sapphire substrate, or a ZnSe substrate), an SOI (Siliconon Insulator) substrate formed by a bonding method or a SIMOX(Separation by IMplanted OXygen) method, or the like can be used.

The element separation regions 2304 and 2306 can be formed by aselective oxidation (LOCOS: LOCal Oxidation of Silicon) method, a trenchisolation method, or the like.

In addition, the p well 2307 formed in the region 2306 of thesemiconductor substrate 2300 can be formed by selective doping of thesemiconductor substrate 2300 with a p-type impurity element. As a p-typeimpurity element, boron (B), aluminum (Al), gallium (Ga), or the likecan be used.

In this embodiment, although the region 2304 is not doped with animpurity element because an n-type semiconductor substrate is used asthe semiconductor substrate 2300, an n well may be formed in the region2304 by introduction of an n-type impurity element. As an n-typeimpurity element, phosphorus (P), arsenic (As), or the like can be used.When a p-type semiconductor substrate is used, on the other hand, astructure may be employed in which the region 2304 is doped with ann-type impurity element to form an n well, whereas the region 2306 isnot doped with an impurity element.

Next, insulating films 2332 and 2334 are formed so as to cover theregions 2304 and 2306, respectively (see FIG. 23B).

For example, surfaces of the regions 2304 and 2306 provided in thesemiconductor substrate 2300 are oxidized by heat treatment, so that theinsulating films 2332 and 2334 can be formed of a silicon oxide film.Alternatively, the insulating films 2332 and 2334 can be formed to havea stacked structure of a silicon oxide film and a film containing oxygenand nitrogen (a silicon oxynitride film) by the steps of forming asilicon oxide film by a thermal oxidation method and then nitriding thesurface of the silicon oxide film by nitridation treatment.

Further alternatively, the insulating films 2332 and 2334 can be formedby plasma treatment. For example, the insulating films 2332 and 2334 canbe formed using a silicon oxide (SiO_(x)) film or a silicon nitride(SiN_(x)) film which is obtained by application of high-density plasmaoxidation or high-density plasma nitridation treatment to the surfacesof the regions 2304 and 2304 provided in the semiconductor substrate2300. Furthermore, after applying high-density plasma oxidationtreatment to the surfaces of the regions 2304 and 2306, high-densityplasma nitridation treatment may be performed. In that case, siliconoxide films are formed on the surfaces of the regions 2304 and 2306, andthen silicon oxynitride films are formed on the silicon oxide films.Thus, the insulating films 2332 and 2334 are each formed to have astacked structure of the silicon oxide film and the silicon oxynitridefilm. In addition, high-density plasma oxidation or high-densitynitridation treatment may be applied to the silicon oxide films aftersilicon oxide films are formed on the surfaces of the regions 2304 and2306 by a thermal oxidation method.

The insulating films 2332 and 2334 formed over the regions 2304 and 2306of the semiconductor substrate 2300 respectively function as the gateinsulating films of transistors which are completed later.

Next, a conductive film is formed so as to cover the insulating films2332 and 2334 which are formed over the regions 2304 and 2306,respectively (see FIG. 23C). Here, an example is shown in whichconductive films 2336 and 2338 are sequentially stacked as theconductive film. Needless to say, the conductive film may be formed tohave a single layer or a stacked structure of three or more layers.

As a material of the conductive films 2336 and 2338, an element selectedfrom tantalum (Ta), tungsten (W), titanium (Ti), molybdenum (Mo),aluminum (Al), copper (Cu), chromium (Cr), niobium (Nb), and the like,or an alloy material or a compound material containing the element asits main component can be used. Alternatively, a metal nitride filmobtained by nitridation of the above element can be used. Besides, asemiconductor material typified by polycrystalline silicon doped with animpurity element such as phosphorus can be used.

Here, a stacked structure is employed in which the conductive film 2336is formed using tantalum nitride and the conductive film 2338 is formedthereover using tungsten. Alternatively, it is also possible to form theconductive film 2336 using a single-layer film or a stacked film oftungsten nitride, molybdenum nitride, and/or titanium nitride and formthe conductive film 2338 using a single-layer film or a stacked film oftantalum, molybdenum, and/or titanium.

Next, the stacked conductive films 2336 and 2338 are selectively removedby etching, so that the conductive films 2336 and 2338 remain above partof the regions 2304 and 2306, respectively. Thus, gate electrodes 2340and 2342 are formed (see FIG. 24A).

Next, a resist mask 2348 is selectively formed so as to cover the region2304, and the region 2306 is doped with an impurity element using theresist mask 2348 and the gate electrode 2342 as masks, so that impurityregions are formed (see FIG. 24B). As an impurity element, an n-typeimpurity element or a p-type impurity element is used. As an n-typeimpurity element, phosphorus (P), arsenic (As), or the like can be used.As a p-type impurity element, boron (B), aluminum (Al), gallium (Ga), orthe like can be used. Here, phosphorus (P) is used as the impurityelement.

In FIG. 24B, by introduction of the impurity element, impurity regions2352 which form source and drain regions and a channel formation region2350 are formed in the region 2306.

Next, a resist mask 2366 is selectively formed so as to cover the region2306, and the region 2304 is doped with an impurity element using theresist mask 2366 and the gate electrode 2340 as masks, so that impurityregions are formed (see FIG. 24C). As the impurity element, an n-typeimpurity region or a p-type impurity region is used. As an n-typeimpurity element, phosphorus (P), arsenic (As), or the like can be used.As a p-type impurity element, boron (B), aluminum (Al), gallium (Ga), orthe like can be used. Here, an impurity element (e.g., boron (B)) of aconductivity type opposite to that of the impurity element introducedinto the region 2306 in FIG. 24B is used. As a result, impurity regions2370 which form source and drain regions and a channel formation region2368 are formed in the region 2304.

Next, a second insulating film 2372 is formed so as to cover theinsulating films 2332 and 2334 and the gate electrodes 2340 and 2342.Then, wirings 2374, which are electrically connected to the impurityregions 2352 and 2370 formed in the regions 2306 and 2304 respectively,are formed over the second insulating film 2372 (see FIG. 25A).

The second insulating film 2372 can be formed of a single layer or astacked layer of an insulating film containing oxygen or nitrogen suchas silicon oxide (SiO_(x)), silicon nitride (SiN_(x)), siliconoxynitride (SiO_(x)N_(y) where x>y>0), or silicon nitride oxide(SiN_(x)O_(y) where x>y>0); a film containing carbon such as DLC(Diamond-Like Carbon); an organic material such as epoxy, polyimide,polyamide, polyvinyl phenol, benzocyclobutene, or acrylic; or a siloxanematerial such as a siloxane resin. It is to be noted that a siloxanematerial corresponds to a material having a bond of Si—O—Si. Siloxanehas a skeleton structure with the bond of silicon (Si) and oxygen (O).As a substituent of siloxane, an organic group containing at leasthydrogen (e.g., an alkyl group or aromatic hydrocarbon) is used.Alternatively, a fluoro group may be used as the substituent, or both afluoro group and an organic group containing at least hydrogen may beused.

The wirings 2374 are formed of a single layer or a stacked layer of anelement selected from aluminum (Al), tungsten (W), titanium (Ti),tantalum (Ta), molybdenum (Mo), nickel (Ni), platinum (Pt), copper (Cu),gold (Au), silver (Ag), manganese (Mn), neodymium (Nd), carbon (C), andsilicon (Si), or an alloy material or a compound material containing theelement as its main component. An alloy material containing aluminum asits main component corresponds to, for example, a material whichcontains aluminum as its main component and also contains nickel, or amaterial which contains aluminum as its main component and also containsnickel and one or both of carbon and silicon. The wirings 2374 arepreferably formed to have a stacked structure of a barrier film, analuminum-silicon (Al—Si) film, and a barrier film or a stacked structureof a barrier film, an aluminum silicon (Al—Si) film, a titanium nitridefilm, and a barrier film. It is to be noted that the “barrier film”corresponds to a thin film formed of titanium, titanium nitride,molybdenum, or molybdenum nitride. Aluminum and aluminum silicon are themost suitable material for forming the wirings 2374 because they havehigh resistance values and are inexpensive. When barrier layers areprovided as the top layer and the bottom layer, generation of hillocksof aluminum or aluminum silicon can be prevented. When a barrier filmformed of titanium which is an element having a high reducing propertyis formed, even when there is a thin natural oxide film formed on thecrystalline semiconductor film, the natural oxide film can be chemicallyreduced, and a favorable contact between the wirings 2374 and thecrystalline semiconductor film can be obtained.

It is to be noted that the structure of the transistor included in thepower storage device of the present invention is not limited to the oneshown in the drawing. For example, a transistor with an inverselystaggered structure, a FinFET structure, or the like can be used. AFinFET structure is preferable because it can suppress a short channeleffect which occurs with reduction in transistor size.

The power storage device of the present invention includes a battery. Asthe battery, the thin-film secondary battery shown in theabove-described embodiment is preferably used. In this embodiment, aconnection between the transistor formed in this embodiment and athin-film secondary battery is explained.

In this embodiment, a thin-film secondary battery is stacked over thewiring 2374 connected to the transistor. The thin-film secondary batteryhas a structure in which a current-collecting thin film, a negativeelectrode active material layer, a solid electrolyte layer, a positiveelectrode active material layer, and a current-collecting thin film aresequentially stacked (see FIG. 25B). Therefore, it is necessary that thematerial of the wiring 2374 which also has a function of thecurrent-collecting thin film of the thin-film secondary battery has highadhesion to the negative electrode active material layer and also haslow resistance. In particular, aluminum, copper, nickel, vanadium, orthe like is preferably used.

Subsequently, the structure of the thin-film secondary battery isdescribed. A negative electrode active material layer 2391 is formedover the wiring 2374. In general, vanadium oxide (V₂O₅) or the like isused. Next, a solid electrolyte layer 2392 is formed over the negativeelectrode active material layer 2391. In general, lithium phosphate(Li₃PO₄) or the like is used. Next, a positive electrode active materiallayer 2393 is formed over the solid electrolyte layer 2392. In general,lithium manganate (LiMn₂O₄) or the like is used. Lithium cobaltate(LiCoO₂) or lithium nickel oxide (LiNiO₂) can also be used. Next, acurrent-collecting thin film 2394 to serve as an electrode is formedover the positive electrode active material layer 2393. It is necessarythat the current-collecting thin film 2394 has high adhesion to thepositive electrode active material layer 2393 and also has lowresistance. For example, aluminum, copper, nickel, vanadium, or the likecan be used.

Each of the above-described thin layers of the negative electrode activematerial layer 2391, the solid electrolyte layer 2392, the positiveelectrode active material layer 2393, and the current-collecting thinfilm 2394 may be formed by a sputtering technique or a vapor-depositiontechnique. In addition, the thickness of each layer is preferably 0.1 to3 μm.

Next, an interlayer film 2396 is formed by application of a resin. Theinterlayer film 2396 is etched to form a contact hole. The interlayerfilm is not limited to a resin, and other films such as a CVD oxide filmmay also be used; however, a resin is preferably used in terms offlatness. In addition, the contact hole may be formed without usingetching, but using a photosensitive resin. Next, a wiring layer 2395 isformed over the interlayer film 2396 and connected to the wiring 2397.Thus, an electrical connection between the thin-film secondary batteryand the transistor is secured.

With the above-described structure, the power storage device of thepresent invention can have a structure in which transistors are formedusing a single crystal substrate and a thin-film secondary battery isformed thereover. Thus, the power storage device of the presentinvention can be provided as a thin, compact, and flexible power storagedevice.

This embodiment can be implemented in combination with the technicalcomponents of the above-described embodiment modes and other embodiment.That is, the power storage device of the present invention employs thestructure with the power storage means; therefore, electric power can besupplied to the load without checking remaining capacity of the batteryor changing batteries with deterioration over time of the battery fordrive power supply voltage. In addition, the power storage device of thepresent invention is provided with the circuit that responds to thepower feeder that supplies an electromagnetic wave for charging thebattery whether the power storage device is in a charging state or anon-charging state; therefore, when charging of the power storage deviceis completed or the charging thereof is interrupted due to some cause,unnecessary supply of electric power by an electromagnetic wave can bestopped. Moreover, the power storage device is provided with the circuitthat responds to the power feeder whether the power storage device is ina charging state or a non-charging state, so that the circuit can informthat a plurality of storage power devices are charged by the powerfeeder, and a power storage device to be charged can be selected toperform charging. That is, even when charging of a plurality of powerstorage devices is not sufficiently performed due to electromagneticwave attenuation, the plurality of power storage devices can beseparately charged. Furthermore, since the power storage device of thepresent invention is provided with the counter circuit inside, the powerstorage device can receive an electromagnetic wave with a certain amountor more of electric field intensity, magnetic field intensity, or powerflux density even if the average of electric power is the same.

Embodiment 4

In this embodiment, an example of a method for manufacturing a powerstorage device, which differs from that described in Embodiment Mode 3will be explained with reference to drawings. In this embodiment mode, astructure in which an antenna, a power supply portion, a chargingdetermination portion, and a battery are formed over the same substratewill be explained. It is to be noted that when an antenna, a powersupply portion, a charging determination portion, and a battery areformed over a substrate at a time, and also when transistors formed overa single crystal substrate are used as the transistors included in thepower supply portion and the charging determination portion, a powerstorage device having transistors with few characteristic variations canbe formed, which is advantageous. In addition, in this embodiment, anexample is explained where the thin-film secondary battery described inthe above-described embodiment is used as the battery in the powersupply portion.

First, an insulating film is formed over a substrate 2600. Here, asingle crystal Si having n-type conductivity is used as the substrate2600, and insulating films 2602 and 2604 are formed over the substrate2600 (see FIG. 26A). For example, silicon oxide (SiO_(x)) is formed asthe insulating film 2602 by application of heat treatment to thesubstrate 2600, and then silicon nitride (SiN_(x)) is formed over theinsulating film 2602 by a CVD method.

Any substrate can be used as the substrate 2600 as long as it is asemiconductor substrate. For example, a single crystal Si substratehaving n-type or p-type conductivity, a compound semiconductor substrate(e.g., a GaAs substrate, an InP substrate, a GaN substrate, a SiCsubstrate, a sapphire substrate, or a ZnSe substrate), an SOI (Siliconon Insulator) substrate formed by a bonding method or a SIMOX(Separation by IMplanted OXygen), or the like can be used.

Alternatively, after forming the insulating film 2602, the insulatingfilm 2604 may be formed by nitridation of the insulating film 2602 byhigh-density plasma treatment. It is to be noted that the insulatingfilm provided over the substrate 2600 may have a single-layer structureor a stacked structure of three or more layers.

Next, patterns of a resist mask 2606 are selectively formed over theinsulating film 2604, and selective etching is performed using theresist mask 2606 as a mask, so that recessed portions 2608 areselectively formed in the substrate 2600 (see FIG. 26B). For the etchingof the substrate 2600 and the insulating films 2602 and 2604, plasma dryetching can be used.

Next, the patterns of the resist mask 2606 are removed, and then aninsulating film 2610 is formed so as to fill the recessed portions 2608formed in the substrate 2600 (see FIG. 26C).

The insulating film 2610 is formed of an insulating material such assilicon oxide, silicon nitride, silicon oxynitride (SiO_(x)N_(y), wherex>y>0), or silicon nitride oxide (SiN_(x)O_(y), where x>y>0) by a CVDmethod, a sputtering method, or the like. Here, a silicon oxide film isformed by an atmospheric pressure CVD method or a low-pressure CVDmethod using a TEOS (tetraethyl orthosilicate) gas.

Next, the surface of the substrate 2600 is exposed by grinding treatmentor polishing treatment such as CMP (Chemical Mechanical Polishing).Here, by exposure of the surface of the substrate 2600, regions 2612 and2613 are formed between insulating films 2611 which are formed in therecessed portions 2608 of the substrate 2600. It is to be noted that bythe insulating film 2610 formed over the surface of the substrate 2600is removed by grinding treatment or polishing treatment such as CMP, sothat the insulating films 2611 are obtained. Subsequently, by selectiveintroduction of a p-type impurity element, a p well 2615 is formed inthe region 2613 of the substrate 2600 (see FIG. 27A).

As a p-type impurity element, boron (B), aluminum (Al), gallium (Ga), orthe like can be used. Here, boron (B) is introduced into the region 2613as the impurity element.

It is to be noted that, in this embodiment, although the region 2612 isnot doped with an impurity element because an n-type semiconductorsubstrate is used as the substrate 2600, an n well may be formed in theregion 2612 by introduction of an n-type impurity element. As an n-typeimpurity element, phosphorus (P), arsenic (As), or the like can be used.

When a p-type semiconductor substrate is used, on the other hand, astructure may be used in which the region 2612 is doped with an n-typeimpurity element to form an n well, whereas the region 2613 is not dopedwith an impurity element.

Next, insulating films 2632 and 2634 are formed over the surfaces of theregions 2612 and 2613 in the substrate 2600, respectively (see FIG.27B).

For example, surfaces of the regions 2612 and 2613 provided over thesubstrate 2600 are oxidized by heat treatment, so that the insulatingfilms 2632 and 2634 can be formed of a silicon oxide film.Alternatively, the insulating films 2632 and 2634 can be formed to havea stacked structure of a silicon oxide film and a film containing oxygenand nitrogen (a silicon oxynitride film) by the steps of forming asilicon oxide film by a thermal oxidation method and then nitriding thesurface of the silicon oxide film by nitridation treatment.

Further alternatively, the insulating films 2632 and 2634 may be formedby plasma treatment as described above. For example, the insulatingfilms 2632 and 2634 can be formed using a silicon oxide (SiO_(x)) filmor a silicon nitride (SiN_(x)) film which is obtained by application ofhigh-density plasma oxidation or high-density nitridation treatment tothe surfaces of the regions 2612 and 2613 provided in the substrate2600. In addition, after application of high-density plasma oxidationtreatment to the surfaces of the regions 2612 and 2613, high-densityplasma nitridation treatment may be conducted. In that case, siliconoxide films are formed on the surfaces of the regions 2612 and 2613 andthen silicon oxynitride films are formed on the silicon oxide films.Thus, the insulating films 2632 and 2634 are each formed to have astacked structure of the silicon oxide film and the silicon oxynitridefilm. In addition, after silicon oxide films are formed on the surfacesof the regions 2612 and 2613 by a thermal oxidation method, and thenhigh-density plasma oxidation treatment or high-density plasmanitridation treatment may be performed to the silicon oxide films.

It is to be noted that the insulating films 2632 and 2634 formed overthe regions 2612 and 2613 of the substrate 2600 respectively function asthe gate insulating films of transistors which are completed later.

Next, a conductive film is formed so as to cover the insulating films2632 and 2634 which are formed over the regions 2612 and 2613 providedin the substrate 2600, respectively (see FIG. 27C). Here, an example isshown where conductive films 2636 and 2638 are sequentially stacked asthe conductive film. Needless to say, the conductive film may be formedto have a single layer or a stacked structure of three or more layers.

As a material of the conductive films 2636 and 2638, an element selectedfrom tantalum (Ta), tungsten (W), titanium (Ti), molybdenum (Mo),aluminum (Al), copper (Cu), chromium (Cr), niobium (Nb), and the like,or an alloy material or a compound material containing the element asits main component can be used. Alternatively, a metal nitride filmobtained by nitridation of the element can also be used. Furthermore, asemiconductor material typified by polycrystalline silicon doped with animpurity element such as phosphorus can also be used.

Here, a stacked structure is employed in which the conductive film 2636is formed using tantalum nitride and the conductive film 2638 is formedthereover using tungsten. Alternatively, it is also possible to form theconductive film 2636 using a single-layer film or a stacked film oftungsten nitride, molybdenum nitride, and/or titanium nitride and formthe conductive film 2638 using a single-layer film or a stacked film oftantalum, molybdenum, and/or titanium.

Next, the stacked conductive films 2636 and 2638 are selectively removedby etching, so that the conductive films 2636 and 2638 remain above partof the regions 2612 and 2613 of the substrate 2600. Thus, conductivefilms 2640 and 2642 functioning as gate electrodes are formed (see FIG.28A). Here, surfaces of the regions 2612 and 2613 of the substrate 2600which does not overlap with the conductive films 2640 and 2642respectively are exposed.

Specifically, in the region 2612 of the substrate 2600, a part of theinsulating film 2632 formed below the conductive film 2640, which doesnot overlap with the conductive film 2640, is selectively removed, sothat the ends of the conductive film 2640 and the ends of the insulatingfilm 2632 approximately correspond to each other. In addition, in theregion 2613 of the substrate 2600, a part of the insulating film 2634formed below the conductive film 2642, which does not overlap with theconductive film 2642, is selectively removed, so that the ends of theconductive film 2642 and the ends of the insulating film 2634approximately correspond to each other.

In this case, the part of the insulating films or the like which do notoverlap with the conductive films 2640 and 2642 may be removed at thesame time as the formation of the conductive films 2640 and 2642.Alternatively, the part of the insulating films which do not overlapwith the conductive films 2640 and 2642 may be removed using resistmasks which are left after the formation of the conductive films 2640and 2642 as masks, or using the conductive films 2640 and 2642 as masks.

Then, the regions 2612 and 2613 of the substrate 2600 are selectivelydoped with an impurity element (see FIG. 28B). Here, a region 2650 isselectively doped with an n-type impurity element at low concentration,using the conductive film 2642 as a mask, whereas a region 2648 isselectively doped with a p-type impurity element at low concentration,using the conductive film 2640 as a mask. As an n-type impurity element,phosphorus (P), arsenic (As), or the like can be used. As a p-typeimpurity element, boron (B), aluminum (Al), gallium (Ga), or the likecan be used.

Next, sidewalls 2654 which are in contact with the side surfaces of theconductive films 2640 and 2642 are formed. Specifically, the sidewallsare formed of a single layer or a stacked layer of a film containing aninorganic material such as silicon, silicon oxide, or silicon nitride,or an insulating film such as a film containing an organic material suchas an organic resin. Then, the insulating film is selectively etched byanisotropic etching mainly in the perpendicular direction, so that thesidewalls 2654 can be formed so as to be in contact with the sidesurfaces of the conductive films 2640 and 2642. The sidewalls 2640 areused as doping masks for forming LDD (Lightly Doped Drain) regions. Inaddition, here, the sidewalls 2654 are formed to be in contact with theinsulating films formed below the conductive films 2640 and 2642 and theside surfaces of the conductive films 2640 and 2642.

Next, the regions 2612 and 2613 of the substrate 2600 are doped with animpurity element, using the sidewalls 2654 and the conductive films 2640and 2642 as masks, so that impurity regions which function as source anddrain regions are formed (see FIG. 28C). Here, the region 2613 of thesubstrate 2600 is doped with an n-type impurity element at highconcentration, using the sidewalls 2654 and the conductive film 2642 asmasks, whereas the region 2612 is doped with a p-type impurity elementat high concentration, using the sidewalls 2654 and the conductive film2640 as masks.

As a result, impurity regions 2658 which form source and drain regions,low concentration impurity regions 2660 which form LDD regions, and achannel formation region 2656 are formed in the region 2612 of thesubstrate 2600. Meanwhile, impurity regions 2664 which form source anddrain regions, low concentration impurity regions 2666 which form LDDregions, and a channel formation region 2662 are formed in the region2613 of the substrate 2600.

It is to be noted that in this embodiment, the impurity elements areintroduced under the condition that parts of the regions 2612 and 2613of the substrate 2600 which do not overlap with the conductive films2640 and 2642 respectively are exposed. Accordingly, the channelformation regions 2656 and 2662 which are formed in the regions 2612 and2613 of the substrate 2600 respectively can be formed in a self-alignedmanner with respect to the conductive films 2640 and 2642.

Next, a second insulating film 2677 is formed so as to cover theinsulating films, the conductive films, and the like which are providedover the regions 2612 and 2613 of the substrate 2600, and openings 2678are formed in the second insulating film 2677 (see FIG. 17A).

The second insulating film 2677 can be formed of a single layer or astacked layer of an insulating film containing oxygen or nitrogen suchas silicon oxide (SiO_(x)), silicon nitride (SiN_(x)), siliconoxynitride (SiO_(x)N_(y) where x>y>0), or silicon nitride oxide(SiN_(x)O_(y) where x>y>0); a film containing carbon such as DLC(Diamond-Like Carbon); an organic material such as epoxy, polyimide,polyamide, polyvinyl phenol, benzocyclobutene, or acrylic; or a siloxanematerial such as a siloxane resin. It is to be noted that a siloxanematerial corresponds to a material having a bond of Si—O—Si. Siloxanehas a skeleton structure with the bond of silicon (Si) and oxygen (O).As a substituent of siloxane, an organic group containing at leasthydrogen (e.g., an alkyl group or aromatic hydrocarbon) is used.Alternatively, a fluoro group may be used as the substituent. Furtheralternatively, a fluoro group and an organic group containing at leasthydrogen may be used as the substituent.

Next, conductive films 2680 are formed in the openings 2678 by a CVDmethod. Then, conductive films 2682 a to 2682 d are selectively formedover the insulating film 2677 so as to be electrically connected to theconductive films 2680 (see FIG. 17B).

The conductive films 2680 and 2682 a to 2682 d are formed of a singlelayer or a stacked layer of an element selected from aluminum (Al),tungsten (W), titanium (Ti), tantalum (Ta), molybdenum (Mo), nickel(Ni), platinum (Pt), copper (Cu), gold (Au), silver (Ag), manganese(Mn), neodymium (Nd), carbon (C), and silicon (Si), or an alloy materialor a compound material containing the element as its main component. Analloy material containing aluminum as its main component corresponds to,for example, a material which contains aluminum as its main componentand also contains nickel, or a material which contains aluminum as itsmain component and also contains nickel and one or both of carbon andsilicon. For example, each of the conductive films 2680 and 2682 a to2682 d is preferably formed to have a stacked structure of a barrierfilm, an aluminum-silicon (Al—Si) film, and a barrier film or a stackedstructure of a barrier film, an aluminum silicon (Al—Si) film, atitanium nitride film, and a barrier film. It is to be noted that the“barrier film” corresponds to a thin film formed of titanium, titaniumnitride, molybdenum, or molybdenum nitride. Aluminum and aluminumsilicon are the most suitable material for forming the conductive films2680 and 2682 a to 2682 d because they have high resistance values andare inexpensive. When barrier layers are provided as the top layer andthe bottom layer, generation of hillocks of aluminum or aluminum siliconcan be prevented. When a barrier film formed of titanium which is anelement having a high reducing property is formed, even when there is athin natural oxide film formed on the crystalline semiconductor film,the natural oxide film can be chemically reduced, and a favorablecontact between the conductive film 2680 and 2682 a to 2682 d, and thecrystalline semiconductor film can be obtained. Here, the conductivefilms 2680 and 2682 a to 2682 d can be formed by selective growth oftungsten (W) by a CVD method.

Through the above steps, a p-channel transistor formed in the region2612 of the substrate 2600 and an n-channel transistor knitted in theregion 2613 of the substrate 2600 can be obtained.

It is to be noted that the structure of the transistor of the presentinvention is not limited to the one shown in the drawings. For example,a transistor with an inversely staggered structure, a FinFET structure,or the like can be used. A FinFET structure is preferable because it cansuppress a short channel effect which occurs with reduction intransistor size.

The power storage device of the present invention is provided with abattery. As the battery, the thin-film secondary battery shown in theabove-described embodiment is preferably used. In this embodiment, aconnection between the transistor formed in this embodiment and athin-film secondary battery will be described.

In this embodiment, a thin-film secondary battery is stacked over theconductive film 2682 d connected to the transistor. The thin-filmsecondary battery has a structure in which a current-collecting thinfilm, a negative electrode active material layer, a solid electrolytelayer, a positive electrode active material layer, and acurrent-collecting thin film are sequentially stacked (see FIG. 17B).Therefore, it is necessary that the material of the conductive film 2682d which is also the material of the current-collecting thin film of thethin-film secondary battery has high adhesion to the negative electrodeactive material layer and also has low resistance. In particular,aluminum, copper, nickel, vanadium, or the like is preferably used.

Subsequently, the structure of the thin-film secondary battery isdescribed. A negative electrode active material layer 2691 is formedover the conductive film 2682 d. In general, vanadium oxide (V₂O₅) orthe like is used. Next, a solid electrolyte layer 2692 is formed overthe negative electrode active material layer 2691. In general, lithiumphosphate (Li₃PO₄) or the like is used. Next, a positive electrodeactive material layer 2693 is formed over the solid electrolyte layer2692. In general, lithium manganate (LiMn₂O₄) or the like is used.Lithium cobaltate (LiCoO₂) or lithium nickel oxide (LiNiO₂) can also beused. Next, a current-collecting thin film 2694 to serve as an electrodeis formed over the positive electrode active material layer 2693. It isnecessary that the current-collecting thin film 2694 has high adhesionto the positive electrode active material layer 2693 and also has lowresistance. For example, aluminum, copper, nickel, vanadium, or the likecan be used.

Each of the above-described thin layers of the negative electrode activematerial layer 2691, the solid electrolyte layer 2692, the positiveelectrode active material layer 2693, and the current-collecting thinfilm 2694 may be formed by a sputtering technique or a vapor-depositiontechnique. In addition, the thickness of each layer is preferably 0.1 to3 μm.

Next, an interlayer film 2696 is formed by application of a resin. Theinterlayer film 2696 is etched to form a contact hole. The interlayerfilm 2696 is not limited to a resin, and other films such as a CVD oxidefilm may also be used; however, a resin is preferably used in terms offlatness. In addition, the contact hole may be formed without usingetching, but using a photosensitive resin. Next, a wiring layer 2695 isformed over the interlayer film 2696 and is connected to the wiring2697. Thus, an electrical connection between the thin-film secondarybattery and the transistor is obtained.

With the above-described structure, the power storage device of thepresent invention can have a structure in which transistors are formedusing a single crystal substrate and a thin-film secondary battery isformed thereover. Thus, the power storage device of the presentinvention can be provided as a thin, compact, and flexible power storagedevice.

This embodiment can be implemented in combination with the technicalcomponents of the above-described embodiment modes and other embodiment.That is, the power storage device of the present invention employs thestructure with the power storage means; therefore, electric power can besupplied to the load without checking remaining capacity of the batteryor changing batteries with deterioration over time of the battery fordrive power supply voltage. In addition, the power storage device of thepresent invention is provided with the circuit that responds to thepower feeder that supplies an electromagnetic wave for charging thebattery whether the power storage device is in a charging state or anon-charging state; therefore, when charging of the power storage deviceis completed or the charging thereof is interrupted due to some cause,unnecessary supply of electric power by an electromagnetic wave can bestopped. Moreover, the power storage device is provided with the circuitthat responds to the power feeder whether the power storage device is ina charging state or a non-charging state, so that the circuit can informthat a plurality of power storage devices is charged by the powerfeeder, and a power storage device to be charged can be selected toperform charging. That is, even when charging of a plurality of powerstorage devices is not sufficiently performed due to electromagneticwave attenuation, the plurality of power storage devices can beseparately charged. Furthermore, since the power storage device of thepresent invention is provided with the counter circuit inside, the powerstorage device can receive an electromagnetic wave with a certain amountor more of electric field intensity, magnetic field intensity, or powerflux density even if the average of electric power is the same.

Embodiment 5

In this embodiment, application of the power storage device of thepresent invention in which a battery is charged by radio signals. Thepower storage device of the present invention can be applied to, forexample, electronic devices such as digital video cameras, computers,portable information terminals (e.g., mobile computers, portabletelephones, portable game machines, or e-book readers), or imagereproducing devices provided with recording media (specifically, adevice which reproduces the content of a recording medium such as adigital versatile disc (DVD) and which has a display for displaying thereproduced image), or so-called IC labels, IC tags, or IC cards whichare attached to bills, coins, securities, bearer bonds, certificates(e.g., drivers' licenses or residents' cards), packaging containers(e.g., wrapping paper or plastic bottles), recording media (e.g., DVDsoftware or video tapes), means of transportation (e.g., bicycles),personal belongings (e.g., bags or glasses), foods, plants, animals,human bodies, clothes, daily articles, or electronic appliances.

It is to be noted that in this specification, an “IC card” refers to acard which is formed by embedding a thin semiconductor integratedcircuit (an IC chip) in a plastic card so as to store data. IC cards canbe classified into a “contact type” or a “non-contact type” depending onthe method of reading/writing data. A non-contact type card has abuilt-in antenna and can communicate with a terminal, utilizing a weakelectromagnetic wave. In addition, an IC tag refers to a small IC chipused for identification of objects, which stores data such as its ownidentification code, and is capable of communicating data with amanagement system via an electromagnetic wave. The IC tag has a size ofseveral tens of millimeters and can communicate with a reader via anelectromagnetic wave. An IC tag of the present invention that is appliedto an RFID which performs wireless data communication can be used invarious applications such as card-form objects, labels (called IClabels), or certificates.

In this embodiment, examples is explained in which an RFID having thepower storage device of the present invention is applied to an IC label,an IC tag, or an IC card, and some examples of products having the IClabel, the IC tag, or the IC card.

FIG. 16A illustrates an example of an IC label with a built-in RFIDwhich includes the power storage device of the present invention. Aplurality of IC labels 3003 with a built-in RFID 3002 is formed on alabel sheet (separate sheet) 3001. The IC labels 3003 are stored in abox 3004. In addition, information on a product or service related tothem (e.g., product names, brands, trademarks, owners of the trademarks,sellers, and manufacturers) are written on the IC label 3003, while anID number that is unique to the product (or the kind of the product) isassigned to the built-in RFID in order to easily figure out forgery,infringement of intellectual property rights such as trademarks andpatents, and illegality such as unfair competition. In addition, a largevolume of information that cannot be written on a container of theproduct or the label, for example, the production area, selling area,quality, raw material, efficacy, intended use, quantity, shape, price,production method, directions for use, time of the production, time ofthe use, expiration date, instructions of the product, information onthe intellectual property of the product and the like can be input intothe RFID, so that traders and consumers can access the information usinga simple reader. Although producers can easily rewrite or delete theinformation, traders and consumers are not allowed to rewrite or deletethe information.

FIG. 16B shows a label-form IC tag 3011 with a built-in RFID 3012 whichincludes the power storage device of the present invention. The IC tag3011 is attached to a product, so that management of the product becomeseasier. For example, when a product is stolen, the stealer can be easilyfound out by follow of a path of the product. In this manner, byprovision of IC tags on products, products that are highly traceable canbe distributed in the market. In addition, in the present invention, theIC tag employs a structure provided with a thin-film secondary batteryor a high-capacity capacitor as a battery. Therefore, the presentinvention is effective even when attached to a product with a curvedshape as shown in FIG. 16B.

FIG. 16C shows an example of a completed product of an IC card 3021 witha built-in RFID 3022 provided with the power storage device of thepresent invention. As the IC card 3021, various kinds of cards can beused, such as cash cards, credit cards, prepaid cards, electronictickets, electronic money, telephone cards, and membership cards.

It is to be noted that in the IC card shown in FIG. 16C which isprovided with the power storage device of the present invention, athin-film secondary battery or a high-capacity capacitor can be used asa battery. Therefore, the present invention is quite effective becauseit can be used even when bent as shown in FIG. 16D.

FIG. 16E shows a completed product of a bearer bond 3031. The bearerbond 3031 is embedded with an RFID 3032 provided with the power storagedevice of the present invention, and the periphery of the RFID 3032 iscovered with a resin, so that the RFID is protected. Here, a filler isdispersed in the resin. The bearer bond 3031 can be formed in the sameway as IC labels, IC tags, and IC cards of the present invention. It isto be noted that the bearer bonds include stamps, tickets, admissiontickets, merchandise coupons, book coupons, stationery coupons, beercoupons, rice coupons, various gift coupons, various service coupons,and the like. However, needless to say, the present invention is notlimited to these. In addition, when the RFID 3032 of the presentinvention is provided in bills, coins, securities, bearer bonds,certificates, or the like, an authentication function can be provided.With the authentication function, forgery can be prevented.

As described above, the RFID provided with the power storage device ofthe present invention can be provided for any objects (includingcreatures).

This embodiment can be implemented in combination with technicalcomponents of the above-described embodiment modes and other embodiment.That is, the power storage device of the present invention employs thestructure with the power storage means; therefore, electric power can besupplied to the load without checking remaining capacity of the batteryor changing batteries with deterioration over time of the battery fordrive power supply voltage. In addition, the power storage device of thepresent invention is provided with the circuit that responds to thepower feeder that supplies an electromagnetic wave for charging thebattery whether the power storage device is in a charging state or anon-charging state; therefore, when charging of the power storage deviceis completed or the charging thereof is interrupted due to some cause,unnecessary supply of electric power by an electromagnetic wave can bestopped. Moreover, the power storage device is provided with the circuitthat responds to the power feeder whether the power storage device is ina charging state or a non-charging state, so that the circuit can informthat a plurality of power storage devices is charged by the powerfeeder, and a power storage device to be charged can be selected toperform charging. That is, even when charging of a plurality of powerstorage devices is not sufficiently performed due to electromagneticwave attenuation, the plurality of power storage devices can beseparately charged. Furthermore, since the power storage device of thepresent invention is provided with the counter circuit inside, the powerstorage device can receive an electromagnetic wave with a certain amountor more of electric field intensity, magnetic field intensity, or powerflux density even if the average of electric power is the same.

This application is based on Japanese Patent Application serial no.2006-236229 filed in Japan Patent Office on Aug. 31, in 2006, the entirecontents of which are hereby incorporated by reference.

What is claimed is:
 1. A semiconductor device comprising: a conductivefilm; a power supply portion operationally connected to the conductivefilm; a flexible battery with a sheet-like form operationally connectedto the power supply portion; and a counter circuit operationallyconnected to the power supply portion, wherein the power supply portionis configured to output electric power, wherein the flexible battery isconfigured to be input with the electric power output from the powersupply portion, wherein the counter circuit counts charging time of theflexible battery, and wherein the counter circuit includes flip flopcircuits.
 2. The semiconductor device according to claim 1, wherein theconductive film is an antenna.
 3. The semiconductor device according toclaim 1, wherein the power supply portion includes a rectifier circuitthat rectifies an electromagnetic wave being input to the conductivefilm.
 4. The semiconductor device according to claim 1, wherein thepower supply portion includes a rectifier circuit and a charging controlcircuit, and wherein the charging control circuit is configured tooutput the electric power.
 5. The semiconductor device according toclaim 1, wherein the power supply portion includes a power supplycircuit, and wherein the power supply circuit controls a voltage levelof an electric signal being output from the flexible battery.
 6. Thesemiconductor device according to claim 1, further comprising a sheetmaterial, wherein the conductive film, the power supply portion, theflexible battery, and the counter circuit are provided over the sheetmaterial.
 7. The semiconductor device according to claim 6, wherein thesheet material comprises a hot-melt film.
 8. The semiconductor deviceaccording to claim 6, wherein the sheet material is an antistatic film.9. A semiconductor device comprising: a conductive film; a rectifiercircuit operationally connected to the conductive film; a determinationcircuit operationally connected to the conductive film; a flexiblebattery with a sheet-like form; a counter circuit operationallyconnected to the rectifier circuit and the determination circuit, andwherein the determination circuit determines whether the flexiblebattery is in a charging state or in a non-charging state in accordancewith a signal being input from the conductive film and outputs a signalfor switching the charging state and the non-charging state, wherein thecounter circuit counts charging time of the flexible battery and outputsthe counted time to the determination circuit.
 10. The semiconductordevice according to claim 9, wherein the conductive film is an antenna.11. The semiconductor device according to claim 9, further comprising: apower supply circuit operationally connected to the flexible battery,and wherein the power supply circuit controls a voltage level of anelectric signal being output from the flexible battery.
 12. Thesemiconductor device according to claim 9, wherein the counter circuitincludes flip flop circuits.
 13. The semiconductor device according toclaim 9, further comprising: a modulation circuit operationallyconnected to the conductive film, and wherein the modulation circuitmodulates a signal to be output to an external portion in accordancewith the charging state or the non-charging state determined by thedetermination circuit.
 14. The semiconductor device according to claim9, further comprising a sheet material, wherein the conductive film, therectifier circuit, the determination circuit, the flexible battery, andthe counter circuit are provided over the sheet material.
 15. Thesemiconductor device according to claim 14, wherein the sheet materialcomprises a hot-melt film.
 16. The semiconductor device according toclaim 14, wherein the sheet material is an antistatic film.